havenrpg has a pretty sizeable Jojo cast, with both Josuke and part 3 Joseph -- I AM OF COURSE SUPER BIASED FOR KIRA, but Kars would be super awesome too. The game is medium-paced, it picks up during events but it's pretty easy to keep up with, and it's extremely backtag friendly! Characters retain their powers unless they have something particularly gamebreaking (to give an example, Crazy Diamond's fixing ability is capped, but its healing ability is 100% intact), and the game is pretty engaging in regards to plot and so on!