Nothing is known about Fermin's background.
Fermin is first seen in mission "The Gunslinger's Tragedy" where he can be seen being hostage by Banditos. Fermin can also be found playing Poker in Chuparosa, but can also be occasionally found in the cantina. He can also be found at Manzanita Post smoking at the campfire or loitering in the General store. He can also be seen at the Pacific Union Railroad Camp doing odd jobs.