No he didn't, he used a regular slash to kill Nnoitra, I already told you that, again, just read the manga.
Kenpachi doesn't control his limiter, it is an unconscious thing, and it says match their power, not exceed it, again, these are both things stated in the scans that I've had to spoonfeed you.
Idgaf about R1 Yammy, full power Yammy > full power Ulquiorra.


Idgaf about R1 Yammy, full power Yammy > full power Ulquiorra.



It was a special 2 handed move done by kenpachi lmfao.
R1 ulquiorra >> R1 Yammy by feats. R2 yammy has no on panel feats but was considered a bore by kenpachi.
