Spoiler: MintharaBesides working with her to destroy the grove, the only way is knocking her unconscious instead of killing her. Yeah, it's kind of metagamey and you really have to stretch to find a reason to do it in-character. They pretty clearly intended her to be for evil playthroughs only given that's how they launched, and just made her available this way to non-evil ones later due to demand (and people modding it in anyway had some effect on the decision I'd bet).