I’ve got a fluffy who deserves to suffer regardless of genre: Umbra. Alicorn stallion, dark indigo fluff, black mane and tail, pure red eyes. Like blank red, no pupils or irises. He’s got supergenius intellect, a deep raspy voice, no speech impediment, magic powers, and no sanity whatsoever.
He tried to burn the world, in response to his creators dumping him in an incinerator. And that was just the start of it. You could do something about him being tortured in Hell after he died. He died three times before it finally stuck.
This might sound like a brag, but I doubt there’s a fluffy worse than Umbra on this website.
Honestly, I’m vaguely tempted to offer Snowcone for this, since her many game overs mean she can be depicted dying horribly in a multitude of ways without it actually going against canon.
Alternately, Wawa, who will canonically(?) be drowned by Snowcone so if he dies to robots that’s pretty clearly non-canon. Wawa is also very good at tormenting other fluffies and killing foals though, if you’d rather take that route. Both are in my OC list (#3 and #4 respectively).
Technically, Crimson is already dead and in Hell for his many MANY crimes of rape and murder. But if you want to resurrect him or have him face some Hellish torture then go for it
Got a hunting friend fluffy that’d be eager to cut loose and “play” with some fluffies unhindered. Don’t know if that’s something you’d like to include.
Just make sure to have him near/with a red flower, because in “the story of flowers”(the story for my fwufftober that I introduced him in) he always has a red flower or so by him.