The show promised a darker Nick they showed a darker Nick when and how he went after Chavez. He did know her out and drag her back to the basement where he and the group proceeded to threaten her life. For Nick that is a dark action. With the Kelly issue if you expect Nick to go swinging his ax and removing heads. Will not happen that is not Nick. Remember Nick is the one no matte what tries to hold onto the moral high ground. You can pick about his actions to prove different. But the writers intent is no matter what Nick will never succomb to the biest within. The do not call Grimm decapitators for nothing.