Menthuthuyoupi (モントゥトゥユピー, Montutuyupiī), nicknamed Youpi, is one of the Chimera Ant King's three Royal Guards. He the most straightforward of the Royal Guards and possesses a strength that comes from his lack of an ego. However, his simplicity is both a boon and burden. Menthuthuyoupi's belligerent, vehement, capricious, and irascible nature make him a fine, yet, variable soldier.
Chairman Isaac Netero overhears Gon and Killua talking about the Zoldyck Family. The Chairman challenges them into a midnight ball game. The reward? If Gon and Killua win, they will instantly become Hunters without finishing the Hunter Exam. To make the game more interesting, Netero is not allowed to attack them in any way, and there are no restrictions placed on the two boys.
Killua starts the game with his assassination techniques, followed by Gon and his various attempts. Netero, however, remains dauntless.
Killua briefly takes Menthuthuyoupi in a battle and overpowers him. Meanwhile, Ikalgo plans various attempts to escape from Bloster. His weakness takes over, being unable to kill Bloster when he had the chance.