Saveria, Cursed by the Dark

Deathtouch, protection from creatures with power less than your devotion to black (Each {b} in the mana costs of permanents you control counts toward your devotion to white.)
When a player has 10 or less life, if Saveria isn't a Demon, put two +1/+1 counters on it, then it becomes a Demon and gains flying. (This effect lasts indefinitely.)
"Light... has f... forsaken me..."