About his children, didn't one of Vivec's books say that Vivec married and then proceeded to reproduce with Mehrunes Dagon to create thousands of children? (must have been a record or something. They only had a week or an hour or something like that.

)
(He's single now. Must have been a divorce. Or maybe it is cause the Nerevarine whacked Vivec.

)
Anyway, I'm not so sure now. Maybe it was Molag Bal? I always mix up those two. They're both evil and their name starts with the feared M.