Also, the Doma arc has the characters losing their soul if they lose while the Seal of Orichalcos is in play, meaning the loser is left with an empty shell of a body.

Absurdly High-Stakes Game: Shadow Games plus Duel Monsters means the world is frequently at stake.

It can be excused by the fact that the season 5 arc ended up being an RPG and the betrayal did occur in the real past. Seto rebelling against the Pharaoh on his own was intended to be a larger plot point that didn't end up happening, so he ended up brainwashed. This is attributed to Kazuki Takahashi never getting to flesh out the story with Seto and Kisara the way he wanted. Furthermore, though they differ greatly, both visions show Kaiba is quite clearly the Pharaoh's enemy, but in Season 5 he's mostly loyal and the only reason the battle occurs is because he gets possessed. The battle is seen first-hand in Season 5, and is rather underplayed given the amount of foreshadowing and importance given to it before.

Later, in Season 3 another vision of this battle is shown, but it's completely different from the vision showed before. Ishizu shows Kaiba a vision of the battle.

Aborted Arc: Beginning in Season 2 of the anime, the stone tablet that continues to be a plot point for the rest of the series shows Kaiba and Yugi dueling in ancient Egypt.

Abandoned Warehouse: Bandit Keith duels Yugi in an abandoned warehouse that has its own Duel Monsters arena.

He snaps out of it by the end of the following episode, though the dub has him take longer to recover, only snapping out of it during the duel with Mai.

10-Minute Retirement: In the wake of his defeat to Kaiba towards the end of the Duelist Kingdom arc, Yugi suffers a Heroic BSoD and vows never to duel again, saying he is afraid of the way Dark Yugi was prepared to win the duel even if Kaiba was killed as a result.

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