Renard started out as a bad guy, literally in the first episode or so. But then the show took him into different directions. For renard it was always about his daughter, that's what got him in with Black Claw. And Grimm got sucked into a parallel dimension, which is where His mom and aunt appeared, and where everyone got killed. So when Nick broke the spell/killed Death he popped back into his reality where his friends were still alive. To each their own, but I was rather pleased with how they wrapped it up, other than being pissed it was over.