User blog comment:B214/Volume 22 spoilers/@comment-9595671-20160814045836/@comment-1359322-20160814062152

I'm fine with just 1 volume. Having more volumes is not always a good thing, especially when dealing with powerful enemies. There are cases where the authors try to hype a powerful enemy too much that it ended up making the story terrible. In my opinion, Ishibumi dealt with 666 appropriately.