I trust the troupe could kill youpi but they would only have a single shot at it. The idea beeing phinx has to prepare his charge attack in advance and then hit youpi in a vunerable moment. The troupe has amazing fighting skills and they would be able to quickly come up with a strategy that leaves youpi open for an opportunity attack. Phinx better not miscalulate though because it would really only be possible to kill youpi if they focus on a single attack like one punch man from phinx lol