User blog comment:CoolJazzman/Soken Ishida death caused by Yhwach?/@comment-8295743-20130626010130/@comment-3246134-20130626140542

Mayuri knew of Yhwach as stated when he talks to Yamamoto("You failed to kill him 1000 years ago") but still, the didn't thought he would even return, specially after the Quincy extermination