User blog comment:PcRetro/So are Sternritter Human or not?/@comment-1387259-20131006215546/@comment-8669536-20131013093559

It has been stated that Sōken Ishida was already dead when Mayuri experimented on him (chapter 46). And it was stated that Mayuri experimented on Quincy Souls, not living Quincy (chapter 123).