Seamus O'Dell was a Human Augment who lived on planet Tagra IV in the late-24th century. He was a part of the group led by Rhys Darcen that had broken away from Section 31 after the agency had considered, but then declined to use biological agents in the Dominion War. O'Dell would later escaped the Lambda Paz with Chief medical officer Aurellan Markalis, who was assigned to infiltrate the augments, returning to Tagra IV to reunite with the rest of Darcen's group. Markalis was then instructed to take samples of O'Dell's antibodies in order to modify the virus so that augments were immune.