Mebeth is the leader of Trinity, a former Regent, and one of the few people in Sheldar to have a 1/4 D-Ratio. He left the Regents for unknown reasons, presumably because he was disgusted by the way they governed the people. He formed Trinity to expose both the Regents' and the government's oppressive methods. In reality, Mebeth still works for the Regents and formed Trinity to serve as a puppet organization -- an outlet for the people's frustration without any risk of an actual rebellion forming.
Lin brings Ryu and Nina to meet Mebeth and teaches the group how to save Nina. Mebeth gives Ryu his key to open the door to the surface and tells Ryu he must obtain three more from the other Regents in order to reach his goal.
