A military operative working for the private military organization Silverpool. He initially appears posing as Douglas Mahoney, the deceased father of Claire Mahoney, and voices his concern over the girl's safety to Reese, who is investigating the Mahoney household. His cover is blown soon after when he and his accomplice try to kidnap Claire and briefly fight Reese before managing to escape. His team later follows Claire outside a biker bar when they are knocked out and interrogated by Reese. David reveals that Claire hacked Silverpool, and they are hunting her due to potential possession of incriminating documents. Silverpool is later exposed to the public and shut down in order to eliminate competition with Samaritan.
A college student who was Claire Mahoney's rival in the Nautilus challenge. Claire sabotaged his chances by making him the target of an unruly biker. Reese was able to save his life and persuaded him to drop out of the dangerous game.
A member of a Biker bar, which contained one of the clues to the Nautilus challenge. He tried to hit on Claire but she tricked him into attacking one of her rivals. Reese intervened and knocked him out.
A Silverpool mercenary who cornered Claire on top of the Nautilus building. Intent on executing Claire after retrieving the incriminating evidence against Silverpool, he and his men were killed by a Samaritan sniper.