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.
Francis is very, very good at this. His extreme display of retribution against a shopowner who dares to defend himself against Höllental is a good example: leaving his master pinned through the neck to the wall by a crossbow bolt, he coldly smashes in the man's skull against his own counter, then offers the corpse to Stefan. When disgustedly refused Francis returns with a detached and businesslike air to beating the body's head against the counter until it is no longer even remotely head-shaped as Höllental tears himself free, laughing through a perforated and blood-choked throat. This is the first witnessed instance of the brutal violence he is credited with by inference, and to date the messiest.
Immediately crowned by Francis breaking down and sobbing his heart out while Höllental hugs, pets and coos over him... still oozing blood as his throat knits back together. Arisbe and Chess are right to wail, even though they're not in the room.