User blog comment:Xilinoc/Ch. 558 - The Heart of the Wolf/@comment-8669536-20131120161716/@comment-11051098-20131120204251

I was on the same thought myself. It would seem like Sajin's grandfather used the technique himself once, and became a "full animal" after the effect wore off.

I do agree that some Shinigami should die. This is a war, and a war always has fallen on both sides. Killing off all Sternritters, Soldat and Yhwach, with no loss from the Gotei 13, even among the captains, wouldn't make it either logical or exciting.