Oberlin St. Clair is Jeffery Tulley's best friend and also serves as first mate on the Hail Mary. He was held captive by Whitt Roberts on the Idrasil.

During his captivity on the Idrasil, Whitt Roberts performed chemical testing on Oberlin, torturing and prying information about Macallan or Tulley. He also intended to keep Oberlin in order to threaten Tulley, who is his best friend. During his escape from the Idrasil, Oberlin sustained heavy injuries, including a lost pinkie. He was picked up by a Chinese secret agent, Mai Lee, and has been on the run ever since, attempting to evade the keen surveillance of the Blackdoor Group. He possesses a briefcase of some sort that the Blackdoor Group, especially Whitt Roberts and Jason Sterling, seem to want. It is theorized that the briefcase allows for communication with Leviathan.