- Abu Bakr of Badajoz is a Saburid (I've explained this twice before but will again because it's a nice piece of strangeness), inspired by RL strangely enough - the Slavic Sabur was the founder of that taifa state of Badajoz in our reality. Basically you've got Slavic slave-soldiers taking control -> you've got a state ruled by Slavic military now turned Muslim. So him being Russian is WAD, it's sort of a "Southern Varangian ghulams turned rulers" episode. Him being Veliki Knyaz is a localisation issue due to his culture
-the Angra Mainyu issue could be solved by making it its own religion, not sure if that's a good idea.
-No on Satanism...(for various reasons) the "evil" religions are Ahrimanism and Angra Mainyu for now... there's also Eosphorism which is not evil but has Lucifer(very different Lucifer though - I've explained it in thread) at its core.

-Pagan is not a pejorative though, it's just a designation in my eyes... you are right though maybe I should remove that tag, I'll think about it!