User blog comment:Xilinoc/Ch. 540 - The Sword Five/@comment-4207271-20130608052910

Maybe Yhwach/Zangetsu had no memories, so did not know what he was? His instincts likely told him that the real Zangetsu was a hollow, so classed him as such. This caused Zangetsu to not know what he was, and he later did not care? Maybe all he knew was he was Zangetsu and that Yhwach/Zangetsu was also Zangetsu? Maybe it﻿ is as big a shock to Zangetsu as well, that what he thought was the other part of him was a fake.