Sasaki's ability: Zero

Name: Zero, so called since anything +0 is that number

Ability: Can allow the user to use any zanpakuto provided he knows the release phrase and Bankai.

side effects: has no effect on individaul ability, and thus hte user cannot use a zanpakuto unless he steals it from a shinigami or is given it (since a shinigami normally would never relinquish his zanpakuto)

How did you get it: Activation of Bount Cells and wiping of half of hte soul in 1945 by Atomic Bomb detonation.