User blog comment:Sicarius001/Royal Guard and Eighth Division Captain/@comment-5551986-20130423223428

Im going along the lines of Renji replacing Shunsui. However, if not, I got a feeling Love Aikawa will be the next 8th division captain.

Senjumaru Shutara: I think she was the "Urahara" of her time, and no doubt made lots of inventions, but Im going to guess she invented Kido.

Osho: In all fairness, seems to be the most senior of the group, Its hard to say what he created, I have no doubt it was the most vital invention of the 5 im thinking along the lines of hell butterflies/Senkaimon/Maybe even the dangai monster thing/ Reijutsu itself (the knowledge of using spirit particles etc of whatever) and maybe even Hoho or Hakuda.