These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Johan is widely considered to be both the poster boy and a remarkable deconstruction of the trope.
Also, Franz Bonaparta, which is quite debatable as Bonaparta does show regret for his crimes and tries to atone. Whether he succeeded in atoning is another question.
The only thing that could prevent Hartmann from entering Complete Monster territory is the possibility that he is too insane to be responsible for his actions.
Crowning Moment of Funny: There is an unintentionally hilarious moment when Gustav gets hit by the police cruiser.
Johan skips right past it in the first volume and keeps going from there.
One could even say that this series doesn't have one. People are redeemed (sometimes at a large cost) for crimes so heinous even death wouldn't be enough in most series. At the end, even Johan is forgiven by his sister, who says "Even if we were the only two people left in the whole world, I would forgive you."
Tear Jerker: Many, but in particular Grimmer's death. Not to mention the poor guy with his baby in Ruhenheim whose wife was killed and he's crying begging for a gun and revenge.