[Endoperez]

Very nice descriptions! The Obsidian Medium's theme changed a bit too much, though. I thought it too alien to feel, or to be pleased. I'll PM you the description I want to use in the stand-alone mod. Any way, few typos, to be updated for the next version:

"Beowulf cut out the creature's heart and ate it to insure it remained dead." -> ensure
"Liking the scorched land, the Black Phoenix has come to view the Abysians as a kindred race." -> Would it be better as "Taking a liking to the scorched land..."?

The Blood Jarl of Niefel is currently just few hundred years older than the other Niefel (who all have maxage 1000). I'd increase his maxage by quite a bit, to perhaps 2000 or so. Startage would have to also be changed, of course.

I think the Fallen Angel is a bit too powerful as-is. For one, he's physically more powerful than Virtue pretender that Pythium can take, has good magic that's probably easier to use in battles (Twist Fate, Luck, Body Ethereal, Fire Shield). It can also bless itself, and prophetizing it would give Pythium a flying H4 prophet. And while it might not be able to take provinces on first turn, a bless, Alteration 1 (Personal Luck) or any armor (Construction 2) will greatly increase its power.

There are many things you could change or get rid of. Changing Fire magic to Air would keep him more in line with Pythium's other mages.
Getting rid of the Holy magic would give at least some reason not to make him your prophet (Arch Theurg would be the only way to reach Holy 4).
You might get rid of either Fire or Astral, making it less a mage and more a warrior.
Getting rid of the Awe would severely limit its power as an early expander.
Most if not all angels are Magic Beings, which makes them weak against certain spells and items. Giving him the Demon tag would give even more counters.
It might have lost its lightning resistance (vulnerable to the wrath of heavens).