I do not know what roles there could be, beyond one to kill. If I recall correctly, he did not elaborate either.

[...]

Perhaps there would be such a role to make things "fair", if this is truly to be an entertaining game. [Though it depends on their idea of entertaining, which is so far very dubious.] Though I fear the possibility that they would purposely place unsuited people it. People who would not, in fact, use it to help others.

[He's mostly just thinking out loud right now.]