So i finished my first evil run end I can tell you they outdone any other game that allows you to roleplay as an evil character. First thing the grove what bad you can do there: let tiefling children die by the snake byte, then make a pact with tieflings to kill druids together.Plus you can help drow priestess kill everyone in the grove than you can have sex with her late at night end if you can persuade her she can become your ally end help you in future quest. Now answering your question why cure it let it inside become more powerfull bee THE TRU SOUL!! Set this word on fire let it drown in riwers of blood, make the charming dying screams be our hymn of victory. Khmm i got carried away, Larians they don't simply allow you kill every one they give you the chance to become villain with thoughts behind, plots of machination. Example the mersenary give you quest to retrive the chest so you go the kill some gnols then trase of blood gets you to the cave full of mersenaries siged by gnols. You can kill gnols save tham persuede to give you the chest done, or you can make gnoles kill all mersenaries than make gnols to turn on each ohter ufter force suicide the strongest one.