Ithillis had no respect for those that would steal the secrets and artifacts of her people. She followed the people that desecrated Delenar, and wanted to reclaim the artifacts and bestow vengeance on those that dared to trespass the drow holdouts. In the process, she got afflicted with frigid woe.
She was slain by the group of heroes after an intense battle where she incinerated them with a fireball and transformed into two monstrous creatures before she was finally slain by Malys.