User blog comment:Xilinoc/Ch. 540 - The Sword Five/@comment-8669536-20130605182414/@comment-5398287-20130606172558

I had gotten the impression that Zangetsu doesn't actually know he resembles Yhwach from 1000 years ago, nor that he suppressed Hollow Ichigo for the sake of fooling Ichigo. More for the sake of, with what we've seen of Hichigo's personality, protecting him.