Board Thread:General Discussion/@comment-5398287-20130625202043/@comment-11051098-20130628165628

He dislikes the shape of his Shikai, saying that it looks like "something that's made to reap lives". He doesn't use it unless he really has to, although he's skilled in wielding it.

Now, what if his Bankai too has a shape that he doesn't like? Or scares him? Like an even bigger resemblance to "death" or "destroyer of life", making him hesitant and unsure.

Now that I think about the chapter where Kensei apparently tried to make him use a Bankai he has achieved, it seemed like he had to force him to use his Bankai by threatening to have Mashiro killing him.