Genkai and Toguro Chose Opposite Answers to the Same Fear
SPOILER!
Fifty years earlier, Genkai and Younger Toguro fought together. Toguro responded to loss by choosing a demon body that would preserve strength and youth. Genkai accepted aging, limitation and the possibility that everything she built would eventually have to pass to somebody else.
Their final battle happens after Genkai has already given most of her power to Yusuke, making the physical outcome almost predetermined. She fights anyway because the argument between them was never only about who was stronger.
Why it matters
Toguro's tragedy is not that he wanted strength. It is that he built his entire life around never again accepting helplessness, then needed Yusuke to prove that choice was not the only answer.
Debut: Ep 051 - Arch-Rivals