User blog comment:Xilinoc/Ch. 618 - The Dark Arm/@comment-7805464-20150307151137/@comment-24384892-20150308195625

Basically, no one with a reiatsu lower than captain-level can go near him without disintegrating. And even then, I still think you need to be at least Kyouraku's level, and he's one of the senior captains, no ordinary captain.