User blog comment:Xilinoc/Ch. 540 - The Sword Five/@comment-8669536-20130605182414/@comment-8669536-20130606085105

Hokkaidomaster, he has defeated at least three hollows since he got Zangetsu, in chapter 183, chapter 184 and chapter 196. And I don't think Kubo shows exactly everything that happens, so Ichigo probably defeated many hollows during the time he had Zangetsu, Kubo just didn't show the fights.

Will-O-Wisp, I still don't think it's a real Zanpakutō. His sword was a real Zanpakutō when he had Rukia's powers. So Shrieker, Acidwire, Hexapodus and all the other hollows he defeated in the Agent of the Shinigami arc were really defeated by a real Zanpakutō. But all hollows he has fought since he got Zangetsu were completely destroyed. Because Zangetsu might imitate a Zanpakutō, but I still believe it's a kind of spirit weapon, hence why it doesn't work like a normal Zanpakutō. But I think the Zangetsu Ichigo has had since the end of the Lost Agent arc is more like a real Zanpakutō because Ichigo regained his powers because of Shinigami givng him their powers.