Agent Clay was a Bureau for Paranormal Research and Defense agent.
Clay appears in the 2004 Hellboy film, created for the movie and not adapted from an existing comic character.
Movie[]
B.P.R.D. Agent Clay served as Hellboy's handler – as Hellboy's existence was kept a secret from the world at large, he was only allowed outside on specific missions and while under supervision. Clay held this position for a number of years until 2004, when his duties were handed to agent John Myers as director Tom Manning thought Clay was becoming too soft with Hellboy. He and Hellboy have an easy familiarity, if not quite progressing to full friendship, to the point that Hellboy teases him about getting a hair transplant to hide that he's balding.
Despite no longer being assigned directly to Hellboy, he still works alongside him through the events of the film. He acts as backup to Hellboy while they discover Sammael in the museum, and again when they descend into the NY subway system to locate the resurrected Sammael's eggs. While in the subway, assassin Karl Ruprecht Kroenen appears and splits Hellboy from the rest of the group with Agent Clay following as backup. While in pursuit, Agent Clay and Hellboy become separated and Karl Kroenen attacks Agent Clay, stabbing him multiple times before laying Agent Clay down and entering a state of suspended animation himself.
When Hellboy finds the two of them, he calls for medical intervention. Manning opined that Clay was unlikely to survive the injuries he sustained, and the ill-fated agent is not mentioned again.