Orphaned as a young child, Marcus spent his time growing up in the streets of Stormwind watching the busy adventurers going about their business. To survive on the streets the young boy fell in with a gang of pickpockets and would have been resigned to a life of crime if not for his foolish bravery in trying to pick the pocket of a paladin knight.
On being captured he quickly saw how his so called friends left him to whatever fate lay in store for him. However, the young paladin had redemption in mind for the young Marcus and took him to the catheral where he was fed, cleaned and admitted into the orphanage. It seems that this had the desired effect on him and eventually the young boy spent hours listening to readings in the catheral and tales of returning paladin knights from far off lands.
When Marcus was of age he was admitted into the order of the Light and became invested as a paladin knight. As a young man in his twenties, he saw many battles and lost many comrades but his desire for spreading the cause of the light was still strong.
In his Thirties, Marcus was part of the expedition which later split away into the Scarlet Crusade, sickened by the fanaticism of this growing cult, Marcus returned to Stormwind to report word of this new threat to the church and demanded a force be raised to deal with the new threat. The church decided that it would be unwise to spread it's forces and would have a detrimental effect on the morale of its troops. Secretly the church feared that its own forces would be swayed to the banner of the Scarlet Crusade. Marcus' frustration at the church was no secret and as a result he was sent to the Azeroth Templars to act as the church's envoy. He believed that he was being sent away, actually he was requested by the Templars Paladin Class Commander - Talgol, the man who had pulled him off the streets all those years ago.
On his first mission for the templars, Marcus was part of a team sent into the deadmines to retrive the head of Van Cleef. Faced with a heavy oak door blocking the way to the hidden boat of Van Cleef, with no key or rogue present to open the lock. Marcus heaved his mallet above his head and knocked the door down, as a result his teammates coined the nickname "Doorknocker" for him. This seemed to stick and he gave no protest. Thus...DOORKNOCKER was born