A hidden society of mutants who live in the sewers. Most have physical deformities because of their mutations or suffer from emotional or psychological issues. Though they are weary of the outside world they have a well structured and well meaning society and are always open to new "citizens".
They are lead by a council of "veterans" who are mostly founders of the society. They have no interest in the fight of mutant coexistence/domination, and simply wish to be left alone.
They have specially selected soldiers who patrol the tunnels around their homes and act as a defense squad.