I think I found this story on Hentai Foundry many years ago but I suspect the original writer has either deleted it or their whole account.

It was a multi-chapter story about a very crude female barbarian in a fantasy(?) world. Lots of killing, gore, but also had a lot of farting and scat - the mc herself basically being a shitting machine.

Looking for it cus I remember one particular scene in which she's visiting a captured castle and finds the former princess turned into a quad amputee and chained down as a toilet. Then proceeds to practically drown the girl in her feces.