I am working on a story idea with a little bit of a comic book, superhero element and I realize that one of my character's background stories is getting rather dark. No actual violence as far as punching, kicking, stabbing, etc. but I still want to make sure I won't be running afoul of any rules. Basically as a child the character was experimented on with gene-splicing and describing some of the villains previous attempts is a bit rough. I don't go into graphic details (just kind of a broad overview to give the reader an idea that terrible things happened and people died and suffered in the process).
The violence rule only really applies to extreme violence + sex (things such as Guro content or going Patrick Bateman on a ho after boning her). Plenty of my stories have involved violence, slurs, adult themes, death, etc and I haven't been banned (or even warned) yet.
I want to have a story where a girl's teeth is knocked in with a hammer (she deserves it), since exceptionally painful rape, spamkings, etc. are all allowed, I'd like to think this and amputation then death is all okay, but I'm sure it probably isn't, at least not the way I'd write it (someone tragically seeing the love of their life die and they find love again after thinking they won't, vs my tale of a girl running from her next spanking and falling in an ant nest.
Depends on the depiction. It might very well be not acceptable, but it depends on the circumstances and depiction.