User blog comment:Salubri/Final Fight: Reflections of an Unrealistic and Ridiculous Battle/@comment-1272757-20100204164331

Well, Gin did bifurcate Hiyori when she attacked Aizen, so perhaps he's just standing by because he has faith in Aizen's abilities (if you recall the little speech he gave about Aizen's abilties), and will intervene when he thinks Aizen's really in trouble. Some things that has popped into my mind though: if Aizen's shikai has absolute hypnosis, then what are the powers of his bankai (my money's on reality warping to whatever degree), and was Tosen the only one to recieve Hollowfication?