I don't think the Guild has any real rules against this. I know there's a general PG-13 guideline but that seems to be mainly in regards to sexual content (in other words, no smut please). I haven't really seen any other sort of explicit content become much of an issue.

As for my personal opinion? Do whatever you like with your characters. :hehe I know I've been guilty of torturing my own characters in the past. Though, that was mostly mental/emotional torture (whereas I assume you mean physical), but still.