Interdimensional Domination Interdimensional Domination , referred to colloquially as the Dimensional War , is the term used to refer to the prolonged hostilities between the Fusion Dimension and the Xyz Dimension . It consequently serves as the main conflict of Yu - Gi - Oh ! ARC - V and stems from Duel Academy ' s Head Professor Leo Akaba ' s desire to " unite all worlds " , and this goal is referred as " Arc Project " . Background . In the Beginning . Sometime prior to the beginning of Yu - Gi - Oh ! ARC - V , Leo Akaba stepped down from the presidency of the Leo Corporation in the Standard Dimension and became the Head Professor of Duel Academy in the Fusion Dimension . There , he sent an army of Fusion users to invade the Xyz Dimension , all with the intention of uniting the worlds . In order to facilitate the invasion , Dennis McField was sent to scout Heartland City for Lulu Obsidian , who Leo wanted captured . Once found , the invasion proceeded with the complete annihilation of the Xyz Dimension . In the wake of the invasion , a resistance was formed by the survivors of the dimension , who rallied together in order to repel their attackers . Sometime after this , Lulu was successfully captured by Yuri , causing Shay Obsidian and Yuto to turn their attention to the Standard Dimension in search of clues to her whereabouts . Current Timeline . Upon learning of Zuzu Boyle ' s existence from Sora Perse , who had been sent to the Standard Dimension for reconnaissance , Leo sent Yuri to capture her . Unknown to Leo , Celina escaped to the Standard Dimension along with Barrett at the same time in an attempt to prove her worthiness of being a Duel Soldier for the Fusion Dimension forces . Upon learning this fact from a defeated Barrett , Leo then sends Sora and a battalion of the Obelisk Force to Paradise City to return Celina to Duel Academy . Both teams eventually failed in their mission , with Zuzu escaping to the Synchro Dimension with Yugo and Celina successfully defended by the soon - to - be members of the Lancers . During the Lancers ' journey to the Synchro Dimension , Dennis who had been working undercover as a spy in the Lancers was discovered and returned to Duel Academy to recuperate by Sora , who had begun to harbor thoughts of defection upon learning of Leo ' s interest in capturing Zuzu . Upon learning from Dennis that both Zuzu Boyle and Celina were in the Synchro Dimension , Leo Akaba sent Yuri , Barrett and twenty Obelisk Force soldiers to invade the Synchro Dimension . Similar to the attack in Paradise City in which retrieval of the targets was the only objective , only small numbers of Fusion users were sent to New Domino City . This time , though , with most of the Lancers separated and kept at the Underground Labor Facility , it became more difficult to defend both Zuzu and Celina . Against the advice of the kids that were looking after her , Zuzu escaped from the Underground Facility , where she had been hiding , and went to successfully find Yuya Sakaki . Meanwhile , thanks to Crow Hogan , the defeated Lancers of the Friendship Cup learned of the small invasion and successfully escaped , but they were too late . At the same time the events at the Underground Facility took place , Riley was too tired and traumatic to defend Celina , and Yuya was locked in a difficult battle with Barrett . Sora appeared and declared his alliance with Yuya , but he was only able to prevent Celina ' s capture by a little more time . Jean - Michel Roger , head of Security , turned out to be a traitor of Duel Academy who intended to use Celina and Zuzu as his lifeline to save himself in case his plans go wrong and his betrayal exposed to Leo Akaba and thus wants both girls captured . Roger sent Sergey Volkov to the girls ' location and ordered their capture . In the duel that followed , Barrett experienced defeat in the hands of Sergey . But to Yuya , Zuzu , and Sora ' s dismay , Barrett successfully activated the dimensional travel app in his duel disk and managed to succeed in escaping and took Celina away with him . Then Yuya tried to protect Zuzu from capture , but even with Sora and the recent arrival of Moon Shadow , Sergey captured Zuzu . Duel Academy ' s mission ended with partial success . Then Roger ' s plans to takeover the Synchro Dimension ultimately failed and he began his attempt to escape to Duel Academy and save himself through Zuzu . Declan successfully blocked his way while Jack and Crow , the Lancers ' most reliable Synchro allies , created a chance to rescue Zuzu . Unfortunately , Roger resorted to his last ditch plan to teleport New Domino into the void between dimensions and capture the Lancers for the Professor . He activated his own interdimensional transport machine , but just like his plans , they malfunctioned and failed and he got pulled into a wormhole . His fate became unknown . Unfortunately , a second wormhole opened up and separated Zuzu , Yuya , Shay , Gong , and Sylvio from the rest of the Lancers , Sora , Jack , and Crow . Declan at this point had no way of knowing which dimension they would end up in . Zuzu arrived at the Fusion Dimension , and rest arrived at the Xyz Dimension . At City , Zuzu learned of the omnipotent and godly status Duel Academy held in the Fusion Dimension . She was able to escape capture from Duel Academy ' s Juvenile Officers who mistook her for a deserter thanks to Alexis Rhodes ' rescue and had a reunion with Yusho Sakaki , Yuya ' s father who went missing three years ago , at the Fusion Dimension ' s You Show Duel School . It was revealed that Yusho was closely connected to the events before the current timeline . In Heartland City , Yuya saw through his eyes the consequences of Duel Academy ' s invasion . He , Gong , and Sylvio rescued a few survivors of the invasion from Duel Academy soldiers who were determined to turn every single survivor into cards . Around this time , he was able to talk to Yuto more often and with a freedom compared to previously . His group of Lancers Dueled against Kite Tenjo , and joined the surviving Resistance members . At the hideout , they found out about the second , debilitating offensive Duel Academy undertook in Shay and Yuto ' s absence as well as Kite ' s personal tragedy . To Yuya ' s shock he also learned about his father ' s visit three years ago . This lead to Yuya ' s search of his father , and he encountered Aster Phoenix , commander - in - chief of the Duel Academy ' s forces , and both Yuya and Yuto dueled him that ended in a DRAW .