User blog comment:Savalric/Hitsugaya Boss/@comment-5657895-20130912063125/@comment-11051098-20130913145114

@ AldenHeathcliffe:

Kenpachi was cut up quite a bit by Nnoitra in their fight, but he didn't die. Unohana apparently killed him countless times during their fight in Muken, but she healed him every time. I don't know if he could manage to fight Byakuya's Bankai at the hands of Äs without dying, but if he could manage to fight his fear of Unohana dying (if she's still alive), I think there is a chance he could win.

Äs' true ability is to implant fear in his opponents, and Kenpachi is one of the few characters in the series who's shown to have very little fear. I think his reaction at Unohana's death (by her words) is the only time I have seen him display something reminiscent of fear. But of course it would have been easier also for him to fight Äs if the latter didn't have Byakuya's Bankai.