Merlyn was one of the world's greatest archers and despite his great skill, never placed himself in a leadership position. Although not exactly a mercenary, Merlyn often worked for different organizations, trying to find out his true loyalty.
A good friend of Oliver Queen, Tommy often joined him in practising archery, with both growing quite skilled at it. Merlyn often joined Oliver at an oil rig, until Oliver's recklessness destroyed it. Tommy fell to what seemed to be his death in the process, in reality he actually ended up in a coma. Waking up in a monastary years later, a disfigured Tommy used makeup to hide his scars and was indoctrinated into being a member of the League of Assassins. Becoming a skilled archer, he was the mentor of Damian Wayne, training him until the boy defected, choosing to rather train under Dick Grayson and the Batman. Merlyn led the Seven Men of Death for the League, being the leader of the elite strike squad. Merlyn's indoctrination was tested and broken when he chose to defect to Leviathan under Talia al Ghul, although was apprehended by Batman Incorporated shortly Battle of Gotham City. With Leviathan left in tatters due to the battle, Merlyn chose to join the Secret Society when the Crime Syndicate took over Earth 0.
Merlyn did not stay with the condensed version of the Secret Society after the fall of the Syndicate, rather he relocated to Seattle. There he began to work as the private assassin of magnate John King and stopped taking care of his burns. Tasked with capturing Mia Dearden, Merlyn quickly found himself in conflict with fellow archer Green Arrow. Quickly recognizing the Arrow as Oliver, Merlyn discarded the million dollar bounty and fled King's service.