S.L. Medley is a marine in Doom 3. He was a Marine stationed at Marine Command HQ Control in Mars City.
Doom 3[]
He is seen at the beginning of the game communicating with Counselor Swann's ship and clearing it for landing. Dr Betruger, who is present, instructs Medley to have Swann sent directly to him.
The player can meet him in HQ Control after Sergeant Kelly gives you your first assignment. However Medley will not be interested in talking with you, and will instead tell you to complete your mission.
His fate is unknown, though he was most likely killed during the demon invasion.