Maou's history is pretty strange and twisting, from both a writing perspective and a story perspective. He always has a 'host' form that he takes, which is the body of whatever mortal he's decided he wants to spend his time with. (It's always way more complicated than that, sshh.)
Here is Maou's host form in 90% of the situations. The old anthro form is retconned to being a transformation state from this one. That's sort of explained in my last sub.
To the mods out there who get worried about the interpretations of the no-human rules, please let me know if this censorship is sufficient. I think it should be okay, but I'll permit myself to be wrong this time.
