Board Thread:Questions and Answers/@comment-36761202-20180909203545/@comment-5398287-20200225013545

I mean, Kubo started planning the final arc after Soul Society and things like the inner Hollow being Zangetsu and Ichigo being a Quincy had been hinted at/foreshadowed hundreds of chapters in advance, but go off and die mad about it I guess.

Oh yeah, and Old Man Zangetsu is half of Ichigo's power, which they said in the manga.