pretty literally dangonrompa. someone gets set as killer, has to kill someone and hide evidence, and once the body is found people convene in a courtroom and try to find out the killer. if the killer gets witnessed, they can try to kill all the witnesses - there's a minimum time after bodies are discovered before court is convened, and killing the witnesses resets it.
you're allowed self defense, but if you kill in self defense you become the killer. the only real way to get back at the killer without killing them is to ensure you leave behind evidence of the killer by either making the death really bloody/easy to find, or find someone and die in front of them or something.
server was hosted by the SapphireServers group, and the whole thing was coded/created by Jack Noir, who quit bl a while ago.