>>724205878
Well, Mir/Mule in AT1 that posted for one. She's not mildly evil either she perpetuated an attempted genocide and a massive war that effectively resulted in a second apocalypse in her region though she did it in retaliation for extremely poor treatment. Eventually she gets her defenses beaten down and sing'd at until she stops trying to kill everyone.
In the second game she becomes a party member and romanceable though she's still loaded down with insanity. It's not until some unspecified point in a song that was released with the final collection of the series' songs that she gets the last of her genocidal hatred purged. She helps save the world in an extremely literal sense too.