I was playing as Sebille with Ifan as companion, and I decided to kill Hannag since she helped annihilate the elves. I was level 13 or 14 and had a devil of a time killing her because of all the Void Portals she conjures on her turn. I had no good way to deal with them since they keep spawning void monsters and appear to only be vulnerable to magic (and the portals maybe keep respawning?) Maybe you just have to defeat Hannag's resurrected form, but she conjures instakill lava. Anyway, I managed to avoid all that. Sebille is has high wits and initiative, so she went before Hannag. I used Adrenaline and Flesh Sacrifice to give her enough AP and chipped off Hannag's relatively low physical armor. Then I turned her into a chicken. (LOVE that spell!) I kept her as a chicken with abilities and scrolls so she could never conjure the portals and respawn. Dead and deader.