User blog comment:Xilinoc/Ch. 631 - friend/@comment-8669536-20150618120459/@comment-8669536-20150619002450

If they are souls the question is "How did they become souls?" I doubt they would have died, so I would have to assume they used some kind of Reishi-conversion technique. They also would have needed something like that to enter Soul Society in the first place. But then does being made of Reishi guarantee a prolonged life?