Weasel

Weasel is the oldest of the Knights (84 years old), but nevertheless a nimble fighter. He is easily distinguished due to his eccentric appearance with a tree growing out of his head containing all his magic power, and always seen holding a wood cane inside which he hides all his ÄRMs. As a Chess Piece he's wicked, but is overall an amicable figure to his Chess fellows, and is civil enough towards his opponents. In the 1st War Games, Weasel fought Jack's father, Jake and grasped victory using his Guardian Bird of Rotten Wood, leaving Jake fatally wounded (and dying at his home shortly thereafter, which was unknown to Weasel).

He plays little to no role in the 2nd War, save for once in the War campaign when he took over an unnamed castle by his trees, and like most of the Chess Pieces spends the War Games observing the fights. He takes special notice of Jack since his debut of victory, for the boy also masters his wood element and uses Jake's memento scoop. He fights Jack in the final round of the 2nd War Games and is defeated by him, who used Kikazoku Fire to burn the tree on his head, eliminating the source of his power. Weasel compliments Jack by telling him that he has surpassed his father, and after the War Games ends, receives no more lines for the rest of the series. Weasel is a plant Guardian ÄRM user.