You don't need to go on the darknet to find gore content, everything is available on the clearnet (at least what's legal to watch). On the darknet, you can quickly stumble upon illegal content even if you weren't looking for it..
If you really want to go for the most extreme stuff, go to goreflix, that's the site with the most extreme content available on the clearnet (and some really f - cked up users if you ask me but members of gore sites tend to be creepy, weird, racist, homophobic, sexist etc, you probably already know that).
I personally can't watch anything related to animals and children.
Most extreme content definitely comes from Middle, Latin America.