User blog comment:Tinni/Ichimaru Gin/@comment-1706259-20100530213457

That is true; every character is at least a bit mysterious.

The difference between Kisuke and the next bleach character is that he is a central figure in the life of the main character. He trained him personally; and in extension through Yoruichi (with his Bankai training). He has taught Ichigo almost everything he learned (besides Ichigo gaining experience in fights.) So this makes Kisuke appealing since he is so involved.

Isshin and Gin I can agree with. Personally I'm not that interested in Kisuke as much as I am in Aizen sama. This guy has a real mysterious persona.