Rieklings compared to the other Goblin variants are a bit more chill and can actually be reasoned with, you can befriend them in the Skyrim DLC I think. They also have their own Language and some Skaal think they are the degenerated descendants of the Snow Elves. You probably could have just brought them into your empire.
I can't even get it to work. I installed it manually, followed the instructions to the letter, the mod does show up in the launcher and I have enabled the playset. When I launch the game it's just vanilla CK3. Don't know what's wrong, my game version is 1.11.5
