A Mentor is a role whose Night action is one of the following:
If the Mentor does not have a living Mentee, at Night they can recruit one.
If the Mentor does have a living Mentee, at Night they or their Mentee can kill someone (unless the Mentor already has a factional kill).
A Mentee is a player who has been recruited by a Mentor. They can talk to the Mentor at any time, but will die if the Mentor dies. (If the Mentee dies, that just frees up the Mentor to recruit someone else during the next Night.)