For years now I have had a giant Black African millipede.
That is no longer the case due to a mistake on my part.
I keep dubia, which are not as cannibalistic as Eublaberus or Blaberus in my experience. I've also been keeping superworms with them without any discernible issue.
I decided to put my millipede in with my roaches.
The next day I found an empty millipede shell. I don't know if they killed her and ate her, or if she died and they ate her. I don't believe she was molting, the most likely scenario to me is that she died of the stress of going from a solitary life to being in a colony of roaches; and then they ate her. At least, I hope so.
Anyway, for anyone Googling, please do not keep roaches and millipedes together.