Trine was a Serra Angel who had been summoned by Archmage Xarl Angel-Keeper. Xarl placed a Horned Halo on Trine's head, binding her to him and making her a fallen angel. She killed thousands, if not millions of people through sacrificial means and/or through war.
Eskil, Xarl's great-great-grandson summoned the Serran Angel Rahel to fight Trine and free northern Corondor. When Trine's blood splashed him upon dying, he was blinded, his skin and hair were bleached white, and he ascended.
Trine reverted to a Serra Angel in death and was carried off to the heavens.