User blog comment:Derax-Pagani/Chapter 507: Voice/@comment-7418318-20161024153946/@comment-7418318-20161025062123

I wouldn't call one definite time and two kinda sorta times a common occurance.

Mavis wasn't really dead and Precht only had his post-mortem moment due to a one-of-a-kind (or two depending on how you want to count Bloodman) Demon, so again not the real thing.

That leaves only Roubaul as the sole definite ghost of a deceased.