Invasion of Xyz Dimension

The invasion of the Xyz Dimension was an event in the Yu-Gi-Oh! ARC-V anime.

History
Reo Akaba the Professor of Academia, ordered his elite vanguard squad to advance into the Xyz Dimension and attack, as part of his plan to eventually unite the Four Dimensions. Without warning, they did so, causing chaos with powerful monsters like "Antique Gear Chaos Giant" and sealing nearly all of the inhabitants of Heartland City in cards in the process. Yūto, Shun, Ruri Kurosaki and a few others were the only survivors of the attack including, although Ruri was captured some time later.

In the aftermath, Barrett was sent to the ruined Heartland City on a mission with a few of his own comrades, but they were attacked by a "All-Purpose Landmine Glaymore" Trap Card. At some other point, a Synchro Dimension Duelist named Yūgo appeared in Heartland, and was challenged by Yūto. Their dragons fought each other until Yūto's allies appeared, at which point Yūgo retreated.

Seeking to avenge their comrades, Yūto and Shun traveled to the Standard Dimension and began attacking the members of Leo Duel School that used Fusion, sealing them into cards. Yūto attacked Shingo in defense of Yuzu Hīragi before learning that most students of LDS were oblivious to the situation, while Shun attacked LDS members indiscriminately, including Marco and Tio, sealing them into cards. Shun's attacks only stopped when he came face to face with Reiji Akaba, the person he had wanted to lure out the entire time, after a fight with Masumi, Hokuto Shijima, and Yaiba Tōdō, where the former was looking to avenge her teacher.

Shun was intent on defeating Reiji and holding him hostage so that Leo would release Ruri. However, Reiji told him that his plan was in vain as Reiji mentioned Reo would not be interested in rescuing Reiji, and instead proposed an alliance as they were fighting the same enemy, which Shun accepted.