What're the different kinds of session? I know doomed and dead sessions are a thing, but what else?

There are three kinds of bad sessions: null sessions, dead sessions, and void sessions. An example of a void session is the Alpha kid’s session. A void session is when nothing is prototyped pre entry. This means the battlefield cannot evolve and grow and the session will go on forever because the Black and White king’s war will be an eternal stalemate.