Dorcas was once a Stormlands Knight who deserted after his King and Leige Lord was slain on the battlefield. Even before his desertion he was a known to take interest in younger boys. Only knighted because he was an effective killer as any Knight should be, known for weilding a large axe and being silent.
The Second Era
Over the years gone by since the war, Dorcas took in all kind of men in his fast growing party. His strength and intimidation suited the bandit lifestyle well.
Soon enough merging all the bandits under his rule through sheer force and fear. He let the bandits do as they please and takes what he wants from anything that is taken into the camp. This group was called The Kingswood Children.
The Third Era
Once they got big enough and known in Westeros people from all walks of life began to make their to the Kingswood to live amongst the free and dangerous gang, large enough that Dorcas had to assign sub-leaders for the half dozen camps spreading throughout the large Kingswood.
Rumor had it that Dorcas named the bandits the Kingswood Children as a guise to lure young boys into the forests so he could take them and fulfill his sick desires. His men knew, but they did not dare to question his ways as it meant certain death.
The Hunt for the Children/Dorcas Death
When the The Kingswood Children were slain by the Queen's men Dorcas engaged in battle with Captain of the Kingsguard Ryman Sunglass, sustaining a mortal wound to his chest. Retreating back he was not to be seen again, it is assumed that he died from the wound later on that day.