Sidenote, I both love that the Knights of Ren are all just unused Jedi Killer concept art-- you can see the helmets to the extreme left and right in the post above-- and I think it is a real shame these guys just get utterly wasted in The Rise of Skywalker, but I don't think they really needed to do anything in that film, either. There's a wonderful tradition of characters suggesting so much more story in Star Wars, and I think just a little clearer framing of these dudes early on would have made them feel a lot more fleshed out.