As peace returns to Heartland City following the World Duel Carnival, Astral, who has collected 50 of the 100 original Number cards at this point, receives a strange vision from within Yuma's key. Meanwhile, an emissary sent by Dumon from the Barian World, named Girag, arrives in Heartland City, and brainwashes a gang of bikers to follow under him, using the spell card Rank-Up-Magic Barian's Force. His appearance revokes a reaction from Shark's sister, Rio. As Yuma, Shark and Tori go to check up on Rio, she utters something about someone planning to take something important, reminding Yuma of the words he heard when first activated the powers of his key. Just then, Yuma receives word that the biker gang's leader, Fender, has attacked his school, demanding he brings his Numbers. Fearing Astral could be put in danger, Yuma leaves his key with Tori as he heads to the school and confronts Fender. As the duel begins, Fender instantly summons his Xyz monster, Mechquipped Angineer. As Astral senses Yuma is in danger, Utopia sends itself over to Yuma, allowing him to summon it and deal some damage. Just then, Fender activates the spell card Rank-Up-Magic Barian's Force to perform a Chaos Xyz Evolution on his Angineer, to upgrade it to the Chaos Xyz Monster Mechquipped Djinn Angeneral, and steal Utopia's Overlay Units.

Angeneral manages to destroy Utopia, despite not being a Number, causing real damage to both Yuma and Astral. Astral makes contact with Tori, asking her to bring the key to Yuma. As Kite and Shark hold off Fender's lackies, Yuma takes more damage from Fender. Tori delivers the key to Yuma, who explains the dreams he's been having to Astral. Encouraging Yuma to stand up and fight with him, Astral gives him the advice needed to bring out Utopia Ray and defeat Fender. After the duel, Kite and Shark reveal they have dealt with all of Fender's allies, while Orbital knocks Fender out, removing the control that Barian World had on him. As Yuma, Shark, and Kite decide to team up to face this new enemy, a mysterious student watches them from the shadows.

On his way to school, Yuma encounters an overly-positive, well-meaning transfer student named Ray Shadows and ends up getting dragged around by him. Meanwhile, a pro duelist named Devon Knox visits the school to have duels with the students. When Yuma expresses his interest in dueling him, Ray takes it upon himself to try and find Devon and convince him to duel. However, Devon is possessed by Girag and violenty duels against Ray to get Yuma's attention. Yuma begins a duel with him and summons out Number 34: Terror-Byte whilst Devon summons out his ace monster, Giantrainer. After using its effect damaging abilities, one of which backfires against him, Devon uses Rank-Up-Magic Barian's Force on Giantrainer to upgrade it into the Chaos Xyz monster Ultimatrainer, using its ability to test Yuma's drawing luck. Yuma manages to survive the effect and use the monster cards he was forced to discard against Devon before bringing out Utopia Ray and winning the duel, freeing Devon from the Barians' control.

After Ray nominates him, Yuma is chosen as the next class president, much to Caswell's dismay. The Student Council President, Carlyle Chesterton, who is under Girag's command, assigns Caswell as a "Special Disciplinary Commander", who begins enforcing harsh rules on the students. As Yuma decides he has had enough and confronts Carlyle, he challenges him to a duel, with Caswell as the referee, throwing in all sorts of rules which obstruct Yuma's dueling. Carlyle summons his Xyz Monster, Norito the Moral Leader, and deals some damage to Yuma, though he manages to find a workaround to Caswell's rules. As Caswell laments how he isn't class president anymore, Yuma reminds him of his true self, allowing him to throw away the role of disciplinary commander. Carlyle then uses Barian's Force to upgrade Norito into the Chaos Xyz monster, Saimon, the Great Moral Leader, but Yuma manages to bring out Utopia and win the duel. Afterwards, Yuma relinquishes his role as class president back to Caswell while Girag finds a new target to put under his control.

A manga artist named Art Stanley requests that Yuma and Shark be models for his manga, but Shark refuses. Unknown to them, Art is under the Barians' control, tailoring Shark to report his weakness to Girag. The next day, Shark discovers that Rio has gone missing and is confronted by Art, who challenges him to a duel. Art quickly summons his Xyz monster, Comics Hero King Arthur, and uses Rio as a means to stop Shark from fighting back, claiming she will become trapped forever if he is defeated. Believing Art's sketchbook may provide a hint to his weakness, Yuma and Ray set off in search for it. Meanwhile, Art forces Shark to summon out Shark Drake and deals a lot of damage before activating Barian's Force, ranking up King Arthur into the Chaos Xyz monster, Comics Hero Legend Arthur, using it to destroy Shark Drake. After some encouragement from Yuma, Sharks calls out to Rio and manages to both free her from captivity and awaken her. Shark soon regains his resolve and brings out Shark Drake Veiss to win the duel.

Rio starts attending Duel Academy, instantly becoming popular with the boys and proving embarrassing for Shark. As Rio manages to overwhelm any club offers with her amazing talent, she and the others are approached by the Flower Arrangement Club's president, Lotus Henazoe, who soons start putting everyone besides Yuma into a trance, revealing herself to be under Girag's control. As Lotus challenges Yuma to a duel, Rio decides to take her on in his place. Lotus summons her Xyz Monster, Battlecruiser Dianthus, and soon uses Barian's Force to upgrade it to the Chaos Xyz monster, Battleship Cherry Blossom, bringing Rio's life points down to 200. Rio soon summons her own Xyz monster, Zerofyne, and manages to use her cards to Lotus.

Noticing Girag's repeated failures, Dumon sends another one of his disciples, Alito, to the Duel Academy, where he ends up getting a crush on Tori. Alito tries to make various attempts to woo Tori, but all of them are inadvertently thwarted by Yuma. Wanting to prove himself, Alito challenges Yuma to a duel, quickly summoning out his Xyz monster, Battlin' Boxer Lead Yoke, and soon realizes who he is up against. Yuma summons his Xyz monster, Gauntlet Launcher, and manages to win by countering Alito's own counters. After the duel, Alito takes a shining to Yuma and declares him his rival.

When Ray makes an innocent suggestion to have a mascot girl for the Numbers club, the resulting arguments causes Tori, Cathy and the others to fall out with each other. Seeing an opportunity, Girag approaches Yuma, who is unaware of his connection to Barian World, and suggests they hold a sports duel tournament to help them make up. The tournament begins the next day, with Yuma and Shark's team pushing ahead while the team consisting of Tori and Cathy lags behind, though they manage to get over their fighting. As Girag arranges a duel between Yuma and Tori's teams, he puts Tori and Cathy under the Barian's control. With Shark going home for the day, Girag ends up getting drafted into Yuma's team, putting him in an awkward situation. Tori summons out her Xyz Monster, Fairy Cheergirl, and uses Barian's Force to upgrade it to the Chaos Xyz Monster, Dark Fairy Cheergirl. However, Yuma manages to summon Utopia and power it up with Girag's trap to win the duel, freeing the girls from the Barians' control.

As Dumon sends yet another Barian emmisary, named Mizar, to Earth, Yuma continues to be plagued with nightmares about losing Astral. Noticing Yuma's lack of energy, Haru asks Tori to take him to Roku's place, where they once again meet Kaze, who gives Yuma some spell cards from Roku. The next day, as Rio suddenly prophesises about a fearsome dragon, Yuma is confronted by Mizar, who traps him in a Sphere Field, forcing him into a duel. Determined to protect Astral, Yuma instantly summons Utopia, using one of Roku's cards to protect his overlay units from Barian's Force. To both Yuma and Astral's surprise, however, Mizar summons an Over-Hundred Number card, Number 107: Galaxy-Eyes Tachyon Dragon, resembling the dragon from Yuma's nightmares.

Using Tachyon Dragon's abilities, Mizar destroys Utopia, knocking Yuma back into the Sphere Field, which deals real damage to him. As Yuma is too weak to continue the duel, Kite arrives on the scene and takes Yuma's place in the duel. Kite summons Galaxy-Eyes Photon Dragon, but struggles against Tachyon Dragon's abilities. However, he manages to survive Mizar's attack and summon out Neo Galaxy-Eyes Photon Dragon, managing to destroy Tachyon Dragon. Just then, Mizar revives Tachyon Dragon and reveals his true form, using Barian's Force to evolve it into Chaos Number 107: Neo Galaxy-Eyes Tachyon Dragon. This, however, turns out to be too powerful for the Sphere Field to contain and Mizar is forced to cancel the duel. As the Sphere Field disintegrates, Shark attempts to catch Yuma, but ends up falling into a crater along with him.

As Yuma and Shark are hospitalized following their fall, Yuma becomes downhearted about his duel with Mizar. Irritated by his behavior, Shark decides to steal Yuma's key to lure him into a duel. Shark instantly brings out both Aero Shark and Black Ray Lancer, dealing a lot of damage to Yuma. Insulted by Yuma's defensive play, Shark brings out Shark Fortress to break through Yuma's defenses. As Shark makes his final attack, Yuma's wishes to keep dueling with Astral brings him to his side, giving Yuma the tactics to turn the duel around, summoning out Heroic Champion - Excalibur and winning the duel with its abilities.

As Yuma and Ray make their way to school, they are pursued by a group of Barian-possessed students and are forced to run. They become cornered, but are assisted by the arrival of Shark, Tori and Rio, who help Yuma fight off the forces of Barian World. Just then, Alito arrives and protects Yuma, defeating all the other students in the process, as he wanted to battle Yuma fair and square. With his alliance to Barian World revealed, Alito challenges Yuma to a duel, activating a Sphere Field along with it. Alito instantly summons Battlin' Boxer Lead Yoke while Yuma summons out Utopia, and the two engage in a battle of counter traps. Yuma eventually manages to destroy Lead Yoke by countering its ability. As Yuma and Alito become excited by the duel, Astral detects something amiss with the Sphere Field.

Alito summons his Over-Hundred Number monster, Number 105: Battlin' Boxer Star Cestus, while Yuma and Astral enter ZEXAL and summons Utopia Ray, both reaching a stalemate. Alito then reveals his true form and upgrades Cestus to Chaos Number 105: Battlin' Boxer Comet Cestus. Yuma then summons the Zexal Weapon - Eagle Claw to equip to Utopia Ray and, after a barrage of counters from both side, manages to win the duel, using the effects of Eagle Claw. As Astral finds he cannot take Alito's Number card (since Over-Hundred Numbers are not a part of his memories), prompting Alito to take his leave, Astral's body suddenly weakens from the exposure to the Barian Sphere Field. Later on, Girag finds a severely beaten Alito, who claims that Ray attacked him before passing out.

As Mizar takes Alito back to Barian World to recover, Girag vows to take revenge against Ray. He issues a duel challenge to Yuma the next day, demanding that he bring Ray with him, believing him to be the one who beat Alito. Deciding to have faith in Ray, Yuma goes to face Girag alone. However, Ray hears about the duel from Tori and Bronk and goes to join Yuma, facing against Girag in a battle royale duel. As the duel begins, with Girag revealing his true form, Yuma immediately brings out Utopia. Girag soon summons out his Over-Hundred Number card, Number 106: Giant Hand, dealing some massive damage to Ray despite Yuma's efforts to protect him. After Astral urges Yuma that protecting Ray is risky, he passes out from the damage caused by the Sphere Field.

Weakened by the Sphere Field, Astral is forced to retreat to the key, which Yuma gives to Tori to look after. Just then, Giant Hand's effect destroys Utopia and deals damage to Yuma, forcing him to play on the defensive. Girag then uses Barian's Force to evolve Giant Hand into Chaos Number 106: Giant Red Hand, with Ray taking damage in order to protect Yuma from its attack. Ray then proceeds to help defend Yuma from Girag's attacks, as well as revive Utopia, before giving Yuma a card called Rank-Up-Magic Limited Barian's Force. Yuma uses this card to evolve Utopia into Utopia Ray V, using it to destroy Giant Red Hand and defeat Girag. Because of the severe injuries Girag suffered during the duel, he is forced to retreat back to Barian World to recover. After the duel, Ray reveals himself to Yuma as a Barian's Guardian tasked with defeating the evil Barians, asking him to keep it a secret from everyone.

As Astral recovers he is once against confronted by Number 96, who tells him he cannot win against the Barian's without accepting his evil side. As Astral refuses this and looks into the Numbers, a mysterious Giant of Shadows appears before him, saying he must be tested, summoning Yuma inside the key and challenging him to a duel. The giant quickly summons out his Xyz Monster, Unformed Void, The Fictitious King, whilst Yuma summons out Number 61: Volcasaurus and Number 6: Chronomaly Atlandis, but the giant is able to use Unformed Void's ability to counter Yuma's attack and destroy Atlandis. Number 96 appears again to remind Astral of his advice, saying that something may happen to Yuma if he loses inside the key. Fearing for Yuma's safety, Astral decides to undo the seal on Number 96, with Yuma reluctantly summoning out Dark Mist, using its abilities to defeat the giant. After the duel, Yuma and Astral are shown Astral's true memories, learning his mission is to obtain a powerful card known as Numeron Code that can shape worlds. Yuma and Astral then return to the real world while Number 96 disappears to somewhere else.

After coming across a romantic movie, Orbital ends up falling in love with Lilybot. Upon misreading a dropped shopping list, believing it to be a cry for help, Orbital assumes Lilybot has been abducted by Yuma and challenges him to a duel. Orbital summons out his Xyz Monster, Googly-Eyes Drum Dragon, whilst Yuma summons out Muzumuzu Rhythm. Although Yuma initially destroys Googly-Eyes, Orbital revives it and powers it up to deal Yuma some big damage. However, Yuma then summons out Tenten Tempo and Melomelo Melody and combines the power of his Musical Djinn monsters to defeat Orbital. After a failed attempt at getting back at Yuma, Tori manages to help Orbital become friends with Lilybot.

Bronk gets the idea that he'll be able to impress Rio if he beats Shark in a duel. After Shark turns down his offer of a duel, saying he is not even at Yuma's level, Bronk jumps to conclusions and soon a rumor spreads around Duel Academy that Yuma and Rio are dating. Believing Shark to be the cause of these rumors, Rio challenges him to a duel, which turns out to be their 100th Dueling Squabble between siblings. Shark summons out Aero Shark whilst Rio summons Zerofyne. However, Rio is put in a pinch when Shark counters her strategy by summoning out Black Ray Lancer. As Shark shows little faith in Rio's confidence as a duelist, Bronk gives her words of encouragement, giving her the courage to summon out Zereort and deal damage to Shark. However, Shark responds by turning her field spell against her summoning out the powerful Shark Caesar and winning the duel. After the duel, it is revealed the rumor was all due to Flip and Caswell's misunderstanding, prompting a swift revenge from Rio.

At the wedding of pro duelist Brook Walker, Anna catches the bouquet containing the spell card, Devoted Love, but she assumes is useless. As Anna decides to visit Yuma during his school's culture festival, Ray informs them of a Couple Duel tournament Umimi and her new husband, Mayday, are hosting, which is said to be Brook's last duel. Wanting to find out more, Anna borrows Tori's school uniform so she can enter the tournament, forcing Yuma to be her partner. Prior to the duel, Brook is approached by Vector in energy form. As Anna confronts Brook over why she wants to quit dueling, they decide to settle things with a tag duel. The duel starts with Brook and Mayday summoning their monsters Unsinkable Titanica and Indestructible Airship Hindenkraft whilst Anna uses Yuma's monster to summon out Gustav Max. Mayday responds by summoning out his Xyz monster, Skypalace Gangaridai, destroying Gustav Max and launching a direct attack at Yuma.

Yuma manages to survive the direct by utilizing his trap card well, and summons Gauntlet Launcher, but Anna ends up using it to bring back Gustav Max, much to Yuma's irritation. Just then, Brook is possessed by Vector and uses Barian's Force to rank up Gangaridai into the Chaos Xyz monster, Skypalace Babylon, with Yuma forced to take damage to protect Anna's life points. As Mayday prepares to launch an attack towards Yuma, Anna uses the spell she received from Brook, Devoted Love, protecting Yuma and allowing him to draw a card at the cost of her own life points. Yuma uses Limited Barian's Force to bring out Utopia Ray V to defeat both Brook and Mayday. Following the duel, Brook reveals to Anna that she isn't quitting dueling but is instead taking a break from it due to being pregnant. Meanwhile, Astral grows concerned about the card Yuma used.

Yuma comes across Ray facing off against a Barian emmissary named Vector, who flees when Yuma arrives on the scene. Ray warns Yuma about Vector, giving Yuma some more Barian cards, reminding him not to tell Astral about them. The next day, Vector appears before Yuma and Astral and forces them to duel him, revealing himself to be the Barian emmisary that possessed Dr. Faker. Vector summons out Number 66: Master Key Beetle and seals away Yuma's Limited Barian's Force card. Yuma summons out Utopia and manages to destroy Master Key Beetle and recover his card, but Vector manages to revive it, recover his life points and summon tokens to destroy Utopia. As Ray arrives to give Yuma support, Yuma uses one of the cards he received from Ray, V Salamander, to revive Utopia and evolve it into Utopia Ray V, using V Salamander's effects to defeat Vector. Just then, Vector captures Ray and takes him to the Barian World, leaving Astral with Number 66: Master Key Beetle, which Vector said is the key to their final battle.

Kite arrives just as Ray is taken into Barian World. After cowering to Kite, Yuma is slapped to the ground, being told to toughen up. Later on, Astral discovers that the Master Key Beetle is the final key to start up the Emperor's Airship. Meanwhile, Shark, Yuma and Kite discuss what to do about Ray. In the middle of their discussion, they are alerted by Orbital 7 that a new anomaly is forming over Heartland City. Just as they arrive at the anomaly, Yuma's key bursts with light and a portal opens above them. The Emperor's Airship passes through the portal and crashes onto the top of the building. Astral then explains what happened with him and the ship. Determined to find Ray, Yuma prepares for the trip to Barian World. Meanwhile, Rio begs Shark to take her, and Shark obliges. The next day Yuma attempts to leave without the family noticing, but instead is surprised and helped by them. The three regroup at the crash site, however the whole gang offers to go on behalf of Ray. Yuma is then appointed captain and each person takes a different station to operate the airship. After entering the portal, they are attacked by rogue duel monsters and soon after sucked into a black hole. Yuma and the others wake up in the interstellae graveyard, Sargasso, where Vector, Mizar and Dumon await. Vector claims that Ray is dead, which enrages Yuma as he prepares to face off against him, with Shark and Kite facing off against Dumon and Mizael respectively. As they summon out their Xyz monsters however, they are suddenly hit by a field effect that inflicts 500 points of damage to each of them (except for the Barian Emperors).

Sargasso is revealed to be a field spell which inflicts damage to players using Xyz Monsters. Vector, Dumon, and Mizar summon their Over-Hundred Numbers: Number 104: Masquerade, Number 102: Star Seraph Sentry, and Number 107: Galaxy-Eyes Tachyon Dragon, while also protecting themselves from Sargasso's effects through the spell card Sargasso's Lighthouse, though Mizar refrains from doing so, in order to fight on equal grounds with Kite. Blinded by his rage, Yuma brings out Utopia Ray V and destroys Masquerade. Just then, Vector seemingly disappears and Ray appears to come back to life, only for him to reveal he was Vector all along. Then, Vector undergoes Barian Battlemorph transforms into his true Barian form. Then, Vector uses a trap to banish Yuma's V cards, restore his life points, and subject Yuma's deck to deck destruction, leaving Yuma with only three cards left in his deck.

Yuma continues to be put under pressure by Vector as he decreases his deck size even further and revives Masquerade. Meanwhile, Shark and Kite summon Shark Drake Veiss and Neo Galaxy-Eyes Photon Dragon respectively, while Mizar uses Barian's Force to summon Chaos Number 107: Neo Galaxy-Eyes Tachyon Dragon. Just then, a black hole appears, threatening to swallow up the spaceship with Tori and the others inside. Vector suggests that Yuma may be able to save them if he relinquishes all of his Numbers. As Yuma becomes conflicted between saving Astral and saving his friends, Tori urges him to keep dueling, while Orbital 7 arrives to assist them in getting the ship to safety. Yuma and Astral attempts to perform a ZEXAL fusion, but it fails due to the small crack of distrust left in Astral due to Yuma using Barian cards and him keeping secrets from Astral. Astral is suddenly swallowed by darkness and forces Yuma to fuse with him, resulting in Dark ZEXAL.

Yuma's conscience wakes up before a large Astral-shaped tower believed to be Astral's heart, facing danger due to Astral believing he had betrayed him. Meanwhile, Astral, in control of the Dark ZEXAL, summons a Dark ZEXAL weapon, Chimera Clad, to power up Utopia Ray V and deal damage to Vector, who activates a trap locking them in an eternal loop. Yuma arrives before Astral, who is becoming envelloped by the power of evil, and embraces him, forcing them out of the Dark ZEXAL union and ending the battle before he loses all of their life points. Vector uses Barian's Force to evolve Masquerade into Chaos Number 104: Umbral Horror Masquerade, though Yuma manages to defend himself by discarding Utopia Ray V and resummoning Utopia, as well as taking advantage of the cards Vector sent to his Graveyard. Regaining their bonds, Yuma and Astral fuse into a new ZEXAL form, ZEXAL II. Then, Yuma uses his new powers to change Limited Barian's Force into Rank-Up-Magic Numeron's Force, and evolve Utopia into Chaos Number 39: Utopia Ray Victory, defeating Vector. ZEXAL II's appearance causes Sargasso to self-destruct, forcing Mizar and Dumon to postpone their respective duels and retreat alongside Vector, while Yuma and the others return to Heartland City.

Frustrated by his loss against Yuma, Vector dives into the center of his planet, into the Sea of Ill Intent, in order to free the Barian God, Don Thousand. Then, Vector offers his life to Don Thousand, and uses his power to resurrect him. Don Thousand grants Vector his power in exchange for locating the seven Legendary Number cards that sealed him away long ago. To achieve his plans, Don Thousand merges with Vector, and briefly possesses him, while restoring his injured body. Vector uses Don Thousand's powers to revive Mr. Heartland as a fly, who had fallen into Barian World since the events of the previous series, and he manages to locate some of the Legandary Numbers with assistance from Mr. Heartland. Then, Vector uses his new powers to accelerate the healing of Alito and Girag. Meanwhile, Astral brings Yuma, Tori, Shark and Rio aboard the spaceship, informing them of the Numbers scattered across the world. He also shows Yuma a message from Kazuma, saying they will need to obtain the legendary Numbers before Barian World can. As they head to their first location, they end up crashing into Dumon and breaking his Baria Lapis, who ends up in a jungle, injured and stuck in his human form. Yuma doesn't recognize him, and wants to help him out despite Shark's warning to not trust others so easily. They soon come across a temple. After inadvertently activating a trap, Shark and Dumon, who decides to use the alias Nasch (the name of one of the 2 missing Barian Emperors), become separated from Yuma and the others, forced to go down separate paths. Yuma's group ends up in the legendary Number's chamber, where it is protected by its guardian, Mach, who challenges Yuma to see if he is worthy. Making matters worse, the walls in the room Shark and Dumon are trapped is start closing in, requiring Yuma to win quickly in order to save them.

Yuma's attacks help open the way for Shark and Dumon to escape to safety, but come at the risk of receiving damage from Mach's traps and spells. After Yuma summons out Utopia, Mach brings out his own Number, Number 44: Sky Pegasus, which forces Yuma to take more damage to keep Utopia on the field. As Shark and Dumon make their way through each room, they find murals depicting a tragic legend about a white pegasus. Wanting to learn how the legend ends, Dumon urges Yuma to keep protecting Utopia, believing the legend is about protecting your friends. Although Dumon reveals his true form, after Shark's power repairs his Baria Lapis and he recovers his energy, Yuma chooses to protect Utopia. With Astral helping Yuma find a loophole in Mach's combo, Yuma manages to bring out Utopia Ray Victory and win the duel. Mach explains the rest of the legend before leaving Yuma with the Number card, while Dumon states he will settle things with Yuma next time. Yuma also finds a coin which he believes to be a memento from Kazuma.

As Yuma and co head towards the location of the second sealed Number, Vector goes to see Number 96, who has been possessing a corrupt official, and convince him to join up with him in his search for the Numbers. Arriving at an abandoned castle, Vector feels an odd connection to the place, like he had been there before. As Yuma's group arrives, Rio feels a similar sensation, speaking of a legend behind the castle. Vector and Number 96 reach the central colosseum, where Number 96 comes face to face with the Number's guardian. After accidentally triggering some traps, Yuma's group also wind up in the colosseum, where Vector arranges for a duel between Astral and Number 96, who had obtained the sealed Number. Number 96 instantly summons out Dark Mist whilst Astral summons Utopia, managing to use Dark Mist's ability against him. However, Vector reveals that damaging Number 96 activates some of the colosseum's deadly traps, which are aimed right at Yuma.

Number 96 summons out the sealed Number he obtained, Number 65: Djinn Buster, managing to destroy Utopia deal a lot of damage to Astral by taking advantage of his wish not to hurt Yuma. As Astral turns to defensive play, Number 96 uses Barian's Force to evolve Djinn Buster into Chaos Number 65: King Overfiend, with Astral managing to survive by reviving Utopia. Receiving some encouragement from Astral and another one of Kazuma's coins, Yuma manages to use the trap aimed at him to his advantage and move to safety, allowing Astral to fight without hesitation. Astral summons Utopia Ray, but Number 96 uses Barian's Force again to upgrade Dark Mist to Chaos Number 96: Dark Storm, using its abilities to force the match into a draw. Vector then sets the castle to self-destruct as he and Number 96 escape, but Yuma and the others safely escape thanks to Kite's arrival. As Kite is informed of the situation, Girag and Alito awaken from their slumber.

Yuma and the others travel to Spartan City in Rome, where they learn of a duel tournament that Nistro is participating in, with Dextra serving as his manager. Nistro explains to Yuma how he and Dextra, who both grew up on the streets, found hope in Duel Monsters and wanted to give that same hope to children using his new "Star Man" persona. They then tell them about a legend involve a fighter who made friends with a rival, but was ultimately betrayed and executed, stating that the colosseum where the sealed Number lies is somewhere at the bottom of a lake. Later that night, Alito sets off some bombs to drain the lake, revealing the hidden colosseum. Alito enters the colosseum and defeats the sealed Number's guardian, claiming the Number just as Yuma and the others arrive at the colosseum. Alito, who seems to have no recollection of his friendship with Yuma, puts Nistro under his control and challenges Yuma and Dextra to a tag duel. Yuma summons out Utopia whilst Nistro summons Alito's new Number, Number 54: Lion Heart, dealing a large amount of damage to both Yuma and himself.

Dextra manages to protect Yuma after Alito forces Lion Heart's effect to activate again, bring Nistro's life points to 0, but he is revived due to Lion Heart's overlay effect which restores his life points, though this causes damage to his body. Alito then summons out Battlin' Boxer Cheat Commissioner, which once again forces Utopia to fight against Lion Heart, but Dextra manages to redirect the attack to herself. Dextra then summons out her Xyz Monster, Night Butterfly Assassin, and, unable to prevent Alito from forcing her to fight against Lion Heart, puts all her feelings into her attack in the hopes that Nistro would remember his true desire, getting knocked out in the process. Nistro, regaining control of his fighting spirit, forgoes powering Lion Heart up with Barian's Force in order to fight Yuma fairly. Yuma then summons out Heroic Challenger Excalibur in order to fight a heated duel against him. When Alito tries to interfere and force Nistro to use Barian's Force, Yuma counters with a trap that knocks Alito out. When he is defeated, Alito experiences flashes of a past memory, seemedly that of the legendary fighter, while Nistro is freed from Barian control. Nistro then gives Yuma Lion Heart, before returning to the tournament scene to bring hope to children.

While examining the two sealed Numbers they have obtained so far, Astral sees a visions depicting the people in their respective legends as Dumon and Alito. The group soon arrive at the base of a tall rock structure, the top of which lies the fourth sealed Number. As they start climbing the structure, they hear a strange roar that resonates with Kite's Galaxy-Eyes. They arrive at a strange dojo where they meet a man named Jinlon, who guards the sealed dragon Number. As Jinlon mentions that he knows of Mizar, Astral reveals his findings to the other, believing that the Barian Emperors were once human long ago. Kite then challenges Jinlon to a duel with their dragons on the line, with Jinlon summoning his number, Number 46: Dragluon, also summoning out Protector Dragon, which keeps Dragluon from being attacked. When Kite summons Galaxy-Eyes Photon Dragon, its effects are negated by Dragluon, but Kite manages to use other means to destroy Protector Dragon. As Mizar arrives at the bottom of the structure, Jinlon uses Dragluon's ability to summon Drain Dragon, which uses its effect to add Kite's life point value to its attack points, raising its attack points to 8000. Drain Dragon also has an effect that deals half of its ATK points as damage when it is destroyed.

Kite sacrifices some of his own life points, so that he can weaken Drain Dragon and destroy it with Galaxy-Eyes Photon Dragon without losing to Drain Dragon's effects. Jinlon then uses Dragluon's ability to take control of Galaxy-Eyes, but Kite manages to stop its attack and reobtains Galaxy-Eyes so he can summon Neo Galaxy-Eyes Photon Dragon and defeat Jinlon. After the duel, Jinlon tells the others about Mizar's legend, who had formed a bond with Dragluon. When the village wanted to sacrifice Dragluon to ward off rainy weather, Mizar prepared to sacrifice himself to save Dragluon, but they were both struck down by the king's army. Mizar overhears this legend and denies it, preparing to fight against Kite. However, their resonance causes the dojo to collapse, forcing Mizar to retreat. The dojo then disappears, with Jinlon leaving Dragluon in Astral's hands, warning them of a potential disaster that resonates all too well, who feels his mission is to destroy Barian World, but he decided to give the number to Kite, so that he can defeat Mizar and see who is the true Galaxy-Eyes Master.

Yuma returns home and watches a news report about a stone statue of a commander named Kiraku Souhachi from the Warring States period discovered at Roku's Duel Sanctuary. The statue bears a striking resemblance to Girag, and believing there is a Number card to be found, Yuma, Astral, and Tori go check it out. Girag, having returned to the human world, also sees the report and gets to the statue before Yuma and his friends. A Number card pops out of the statue, but then a tanuki spirit emerges from the statue and possesses Girag. When Yuma and company finally arrive, they are surprised to see that the tanuki spirit, Ponta, is in control of Girag's body while Girag himself is in the statue. Ponta is in fact the Number's Guardian, and Yuma challenges him to a duel with the Number card and Girag at stake. After Xyz Summoning Number 64: Ronin Raccoon Sandayu, Ponta temporarily possesses Yuma and proceeds to waste all of Yuma's cards in a series of misplays. Nonetheless, Yuma manages to win the duel and claim the Number. It is revealed that in the legend of Girag, Ponta was just a stray animal picked up by Girag and had the ability to transform himself into a duplicate of Girag, allowing Ponta to act as his double for battles. However, Ponta was betrayed by Girag, who sent him away before a big battle, making Ponta angry, and his spirit had been sealed in the statue ever since then. Girag defends himself by saying that he drove Ponta away because he knew he was entering a losing battle, and he wanted Ponta to stay alive. Girag, in spirit form, then bursts out of the statue and swallows Ponta, reclaiming his body. He then departs back to Barian World, with Ponta's spirit resting inside him.

As the gang arrive at the location of the final two sealed Numbers, above a stormy ocean, Rio suddenly starts hearing a voice in her head and is drawn towards the ocean; and she dives into it. Shark, Yuma and Astral dive in after her and wind up in a mysterious world underneath the sea, following Rio's footprints to a strange labyrinth, where Shark becomes separated from the others. Arriving at a temple in the center of the labyrinth, Shark finds Rio, who has been possessed by the Number's guardian, Abyss, and is challenged to a duel. Sharks summons out Black Ray Lancer while Abyss summons out Gorgonic Guardian, using its powers to destroy Black Ray Lancer. When Abyss projects a strange light, Shark sees a vision in which he and Rio were rulers of an ancient civilization, which was attacked by Vector. As Shark's life points are knocked down to 200, Dumon appears before Yuma and Astral.

Dumon states his desire to find the two missing Barian Emperors, Nash and Marin, while Astral responds that his mission is to destroy the Barian World. Meanwhile, Shark encounters more visions while Abyss summons his namesake, Number 73: Abyss Splash. Astral and Dumon are brought into one of Shark's visions, in which Rio sacrificed herself to help Shark fight off Vector, leading to the realization that both Shark and Rio are the missing, former Barian Emperors. As Abyss attempts to sacrifice Rio in the same manner, Yuma manages to save her whilst Shark becomes able to summon Rio's Number card, Number 94: Crystal Zero, and win the duel. As Shark receives Abyss' card, everyone returns to the ship, but Rio remains unconscious.

As various supernatural disasters happen across the world, Number 96 appears and brings Yuma, Astral, Tori, Shark, and Kite to a Chaos Field, forcing Yuma and Astral into a Sphere Field that barrages them with lightning. As the duel goes on, Number 96 manages to summon Chaos Number 96: Dark Storm, before using the field spell Chaos Field to steal Yuma's Number 69: Heraldry Crest and Number 92: Heart-eartH Dragon, and rank them up into Chaos Number 69: Heraldry Crest of Horror and Chaos Number 92: Heart-eartH Chaos Dragon. Number 96 then uses the ability of Heart-eartH Chaos Dragon, which prevents Yuma from activating card effects of cards on the field until the End Phase, making Yuma unable to avoid Number 96's attacks.

After barely managing to survive Number 96's attack, with the ability of Bacon Saver, Astral helps Yuma with his duel. Using the special ability of Heart-eartH Chaos Dragon, Dark Mist raises his Life Points to 7,500, while Yuma only has 500 Life Points remaining. Being unwilling to give up, Yuma and Astral merge into ZEXAL II, and bring out Utopia Ray and two new Zexal Weapons: Sleipnir Mail and Asura Blow. This allows Yuma to overpower Number 96's monsters and defeat him. In a last-ditch attempt, Number 96 uses the last of his strength to try and take over Astral's body, but Astral chooses to sacrifice himself to destroy Dark Mist, leaving Yuma horrified. This action severely drains Astral and forces him to retreat to Astral World, and he entrusts Yuma with the Numbers they obtained, before fading away.

As Yuma remains reclused following Astral's disappearance, Don Thousand gives Vector the remnants of Number 96's power, who is revealed to be a shard of Don Thousand's malice that was trapped inside of Astral, during Astral's ancient battle with Don Thousand. Number 96 is also revealed to be a "Forbidden Number." Then, Don Thousand reveals his plan to use his new powers from Number 96 to make multiple Dimension Fusing Devices, to merge the Human World with Barian World, once the level of evil in the Human World reaches that of Barian World. This would increase Don Thousand's power by a thousandfold, giving him enough power to destroy Astral World. In order to create more Dimension Fusing Devices, Don Thousand emerges from Vector's body in a black energy form resembling his true likeness, and fuses Vector to his throne, in order to concentrate their energy on making more Dimension-Fusing Devices. Then, using his newly enhanced powers, Vector returns Mr. Heartland to his human form, grants him four Fake Number cards, and gives him a group of 3 Barian servants, who, along with Mr. Heartland, make up the Fearsome Four of the Dark Dueling World. Mr. Heartland distributes 3 of the Number cards among the other members of the Fearsome Four, while he keeps Number 1. Soon afterwards, a servant named Semimaru begins attacking duelists and stealing their memories. When Tori and the others try looking into the incident to cheer Yuma up, they are caught by Semimaru, who steals their memories and uses them as bait to lure Yuma into a duel. Heartland attempts to coerce Yuma into giving up his Numbers to save his friends, but he remains determined to cling onto the Numbers that Astral had left him. He is soon joined by Trey, who offers to support Yuma in a 2-on-1 duel against Semimaru. However, Mr. Heartland uses Don Thousand's power (which manifests in a crest-like form of Don Thousand's Barian Emblem) to activate a field effect, which puts Yuma and Trey at a distinct disadvantage

Semimaru quickly summons out the Number he received from Vector, Number 3: Cicada King, using its ability to negate a combo Yuma had planned to use with Utopia. Trey summons Number 33: Chronomaly Machu Mech, managing to damage Semimaru with help from Yuma's cards. However, Semimaru deals a lot of damage to Trey, who took the hit for Yuma, and activates a trap that would ensure Yuma's victory on his next turn. As Yuma struggles to think of a comeback, Tori and the others regain some of their memories and show their support, reminding Yuma that he is not alone. Yuma then sets the stage for Trey to summon Number 6: Chronomaly Atlandis, equip it with Utopia, and use Atlandis to win the duel, destroying Semimaru and returning Tori and the others to normal. Afterwards, Yuma decides to give Cicada King to Trey as a sign of their friendship.

With Vector’s patience for failure fading fast, Mr. Heartland begs for a final chance to beat Yuma! Desperate to deliver, Heartland deploys his most dangerous duelist to date, a treacherous Barian armed with toxic tentacles! Source: crunchyroll

Chironex uses Number 4: Stealth Kragen's ability to summon two Kragen Spawns, bringing back Stealth Kragen and another Spawn when Quattro uses Giant Grinder's ability again. As the poison continues to worsen Shark's condition, Quattro summons Number 40: Gimmick Puppet of Strings, but it has its abilities blocked by Chironex's trap card. After receiving encouragement from Quattro to stand up, Shark manages to summon Abyss Splash and works together with Quattro to defeat Chironex. This allows Shark and Rio to be cured of the poison, and earns Quattro the Stealth Kragen card. Before disappearing, Chironex remembers that he was responsible for the car accident that killed Shark's family. However, he muses that Shark and Rio shouldn't be here, because he remembered that they were killed in the accident. Afterwards, Shark finds an emblem in his family's mansion, similar to the one he saw in his visions of his past life (the Barian Emblem), implying that he and Rio had died in that accident.

As Yuma continues to put on a brave face around the subject of Astral, Flip builds a memorial for him to show everyone's respects. However, Yuma still refuses to acknowledge Astral's death, even when the others try to confront him about it. Just then, Kite appears before him, stating that they may find a way to bring Astral back, if they can find a way into Astral World to search for the Numeron Code. He states that they could use the coins left by Kazuma, which are believed to be fragments of Astrite crystals, to power an interdimentional gate to Astral World. He takes Yuma and Tori to the location of an interdimensional gate he and Quinton built, where they manage to convince Quinton to let him go, despite the dangers involved. As the preparations are made to send Yuma to Astral World, Heartland's third minion, Scritch, attempts to interrupt the experiment, challenging Kite and Quinton to a handicap duel. Quinton and Kite summon Number 9: Dyson Sphere and Galaxy-Eyes Photon Dragon respectively, while Scritch summons his monster, Number 2: Ninja Shadow Mosquito, which is hidden from sight.

After Kite and Quinton discover that Ninja Shadow Mosquito is literally as small as a mosquito, Scritch uses its ability to make Galaxy-Eyes Photon Dragon attack Quinton. Meanwhile, Kite is affected by a mosquito bite he received from Scritch during his journey, which is causing him to confuse his allies with his enemies. Recalling his training days with him, Quinton manages to awaken Kite's inner fire and break him free of the Scritch's influence. With help from Quinton, Kite manages to power up Galaxy-Eyes Photon Dragon and defeat Scritch, and obtain his Number card. After the duel, the interdimensional gate is fully charged, allowing Yuma to go to Astral World.

Arriving in Astral World, Yuma is guided by a Rainbow Kuriboh Kazuma built towards a strange town, where he is attacked by a strange being named Eliphas. Escaping thanks to Rainbow Kuriboh, Yuma receives a message from Kazuma, telling him to save Astral. Meanwhile, Shark, who is conflicted between his childhood memories and Barian memories, is approached by Dumon, who reveals to Shark that he is one of the Seven Barian Emperors, Nash. Yuma is rescued by an Astral being named Ena, who states Yuma can use the power of Chaos to restore the damage done to Astral World, and help its people fight against Eliphas, who has put the town under his control. With Ena's help, Yuma finds where Astral is laying, with Eliphas standing in his way. As the two begin to duel, Eliphas summons his Xyz monster, New Order 4: Etheric Anubis, while Yuma summons Utopia. However, Yuma is soon pushed into a corner when Eliphas exhibits the ability to perform a Shining Draw.

Yuma faces his toughest challenge yet when he battles against an opponent who can draw the exact card he needs every turn! Source: crunchyroll

Yuma fights to free his best friend Astral in a duel he cannot win but must not lose! Meanwhile, Shark comes face-to-face with his past and learns the truth about his Barian background! Source: crunchyroll

With Astral’s fate hanging in the balance, the heart-pounding battle between Yuma and Astral World’s Guardian thunders to its frenzied finish! Source: crunchyroll

To get a lead on Yuma and his buddies, Vector bombards Earth with bogus Numbers. When one of them takes the bait, it puts Mr. Heartland and his sinister swarm of insect monsters hot on the gang’s heels! Source: crunchyroll

With Kite grounded, Yuma and Astral step up to take the buzzing Barian, Mr. Heartland down! Can our heroes repel this pest, or will they end up getting squashed instead? Source: crunchyroll

When all seven Barian Emperors ambush Yuma, some friendly faces drop in to help take the Barians out! Source: crunchyroll

Quattro faces off against the Barian leader, Nash! Hoping to find Shark swimming just beneath his new Barian identity, Quattro looks to hook his old friend and reel him back in! Source: crunchyroll

The back and forth battle between Nash and Quattro comes to a climactic conclusion! Will this battle lure the real Shark out from inside his Barian form, or will it cost Quattro much more than he ever could have imagined? Source: crunchyroll

Looking to get revenge for their brother Quattro, Trey and Quinton team up to take down the treacherous Barian, Mizar! Source: crunchyroll

As Quinton and Trey`s devastating double duel against Mizar flares to a feverish finish, the brothers reveal the real reason they are battling the Barian! Their startling secret hits Mizar harder than any attack! Source: crunchyroll

Yuma and Astral`s race to face Don Thousand is stopped cold by the hot-blooded Alito, now brainwashed by the Barian deity! Can they think fast enough to free Alito of Don Thousand, or will he take the two down for the count?! Source: crunchyroll

Yuma and Astral duel desperately to try and turn an old enemy into their newest ally, but with Don Thousand in Alito’s corner, Yuma and Astral find themselves up against the ropes! Source: crunchyroll

Vector sets his sights on squashing Marin and Dumon, and there’s nothing Shark can do but watch his sister and best friend squirm before his eyes. Source: crunchyroll

The thunderous battle between Marin, Dumon and Vector shatters expectations as it nears its startling end! Meanwhile, Alito stands tall against his former friend, the Barian behemoth - Girag! Source: crunchyroll

Marin`s duel with Vector charges to its climactic conclusion! Can Marin outduel this venomous villain, or will Vector remain invincible?! Source: crunchyroll

The long foreshadowed faceoff is finally here! Kite and Mizar go toe-to-toe to settle who is the one true Galaxy-Eyes master! Source: crunchyroll

The fierce face-off between Kite and Mizar soars to new heights as their battle to determine the one true Galaxy-Eyes master roars to a finish! Source: crunchyroll

Nash races to face Vector, but with Vector`s enhanced strength, he may be speeding towards his own demise! Source: crunchyroll

While Nash and Vector`s danger-fueled duel hits dizzying new heights of havoc, the truth behind Vector’s dark past is revealed! Source: crunchyroll

Yuma teams up with an unlikely ally to take down the great Barian deity, Don Thousand! Can this twosome draw out a victory, or will Don Thousand douse any hope these heroes have of being victorious? Source: crunchyroll

Yuma and Shark’s battle with Don Thousand takes a treacherous turn when the great Barian deity reveals he can rewrite their cards into entirely different cards! Can Yuma and Shark defeat a foe who can change their every move? Source: crunchyroll

Yuma and Shark turn the tides and put Don Thousand on the brink of defeat, but DonThousand still has a thousand tricks up his sleeve! Source: crunchyroll

Once friends, now foes - Yuma and Shark face off in a battle where winning could mean losing everything! Source: crunchyroll

Winning comes with the ultimate price when Yuma realizes victory will cost more than just losing his friendship with Shark, it will mean losing Shark forever! Source: crunchyroll

Expect the unexpected as the game-changing conclusion of Yuma’s duel against Shark flares to a frenzied finish! Source: crunchyroll

Having gathered all one hundred Numbers, Astral is finally prepared to fulfill his mission – to destroy Barian World! But in order to see his mission through, Astral will have to destroy his friendship with Yuma first! Source: crunchyroll

The battle between Yuma and Astral rages on as the best of friends become the fiercest of foes! Source: crunchyroll

Feel the flow for the final time as Yuma and Astral high-five the sky in the cosmic conclusion to Yu-Gi-Oh! ZEXAL! Source: crunchyroll