User blog comment:Xilinoc/Ch. 686 - Death & Strawberry (End of Bleach reMIX)/@comment-5303512-20160819010913/@comment-5398287-20160819043655

Plus I'm sure he was motivated by the state in which he was "born" - completely and utterly helpless. Anything could've killed him in that state, and I think deep down he feared ever becoming so weak again that Yhwach decided to go to these great lengths in order to ensure he'd need never fear death again.