Deltarune snowgrave route

So like in the context of deltarune, theres a route called a snowgrave route where its like genocide but instead of you doing it, its one of the ppl in your party you manipulate to enact it, cause lore and stuff, so in the final battle against this guy, he says som close to this where weve been killing their classmate, a bird, as a result, and hes there to stop this madness, although hes the classical bad guy, in this case hes the hero.