Board Thread:Questions and Answers/@comment-26005711-20160630110509/@comment-26871105-20160703163246

Youpi with his insane shapeshifting and his incredible reserve of Nen makes him outright unkillable unless his Nen runs out. I mean suicide bombing doesn't even kill him, I doubt there is anything that could actually end him outside of running out of Nen or that getting poisoned.

So in a fight between Pitou and Youpi, it pretty much comes down to who runs out of Nen first really, since before that happens Youpi most likely can't even land a single blow on Pitou, while Pitou couldn't do any damage to Youpi.