Awakened

Berserk Mode is an unofficial term used to refer to the state of mind that Yuya, Yuto, and Yugo occasionally enter.

Effects
This ability causes Yuya and his dimensional counterparts to go into a state of rage, and their eyes to glow. This usually occurs in a Duel invoking the Four Dimension Dragons where the dragons overtake their owner's mind, or when the user is sufficiently angered. While they are in Berserk Mode, they are willing to harm or destroy their opponent in order to win the Duel. When they regain their senses, they generally have no knowledge of what happened while they were in Berserk Mode.

Notably, Yuya's Berserk Mode is slightly different from Yuto and Yugo's. Instead of going into a blind, homicidal rage, Yuya is collected and cold, speaking no more than necessary. Additionally, instead of the entire eye, only his pupils begin to glow.

History
It first appeared during the Duel between Yuto and Yugo. When Yuto Xyz Summoned his "Dark Rebellion Xyz Dragon" and Yugo Synchro Summoned his "Clear Wing Synchro Dragon" their eyes glowed (Yuto's eyes glowed blue while Yugo's were green). After being reminded by Yuya that he didn't want to hurt anyone, Yuto came out of Berserk Mode, but then lost to Yugo a moment later.

Later in his Duel against Isao Kachidoki, Yuto appeared in Yuya's mind and the two merged, causing Yuya to enter Berserk Mode and use Yuto's "Dark Rebellion Xyz Dragon" to win the Duel. When Yuya regained his senses, he was met with concerned stares from the audience and disdain from Isao.

During his Duel against Makoto Takeda and Ken Umesugi, "Dark Rebellion" appeared in Yuya's mind and he would have entered Berserk Mode had his ally, Dennis Macfield, not managed to bring him back to his senses before it fully consumed him. Though Yuya did summon "Dark Rebellion", he was able to remain in control for the remainder of the Duel.