... I don't think Sariel's a "True Believer". She just doesn't have anything else in her limited life, so even without the binding power that controlled her before she still follows orders, to the letter, but only that much. I can't really bring myself to hate her, only pity. She's so pathetic, and the way she seems actually pleased with Kurono is just... tragic.
ALSO, DIS LOLI EMPTY! YEET!