User blog comment:Xilinoc/Ch. 568. Hear. Fear. Here 2/@comment-6299840-20140212100929/@comment-4666155-20140212103254

If my understanding is correct, it's not even then. When a Shinigami or soul dies, they're simply reincarnated into the material world as a human (I'd assume human, to keep the balance, I'm not an expert in the cycle of reincarnation). I'd assume the only way to truly 'die', to cease existing entirely,is to have your soul entirely destroyed. And the only ones who can do that are Quincy