Yoren Issarion was always better at breaking things than putting them back together. The son of a serial camp follower he grew up on the amid army encampments and mercenary bands throughout the river kingdoms. His biological father either deserted or was killed while he was an infant and so he had a succession of military men as surrogate fathers, all with wildly varying degrees of aptitude and interest.
From the time he could walk he was getting into fights, many of them about whether his mother was a prostitute (she wasn't, and the proof of that lay in many black eyes and chipped teeth). Wherever he went he developed the reputation as the kid to beat in a fight. No amount of exasperation on his part could dispel this, and it seemed no mater how many heads he knocked together there was always another.
Finally when he was fourteen one fool would not give up, and he wound up dead. Yoren's mother bundled him up and sent him on his way in the night like she always knew it would come to this. She directed him to the location of a mercenary band where an old soldier who fondly remembered his mother got him work first as a messenger, and then a fighter.
Yoren proved to be good at everything mercenaries traditionally do, but he hated it. He was trapped in an escalating cycle of violence, without meaning, with no future. One cold morning while stripping the bodies of slain foes he came upon something different. It was the journal of a pathfinder. The unfortunate soul had been caught between two armies and mistaken for an enemy scout, and outriders had ridden him down.
The journal told the story of a man who was a fighter, but also an explorer and a historian. Who traveled the lands around the Inner Sea
seeking knowledge and recording observations. Who had done many good things for people along the way, with his sword arm, and not for gold.
Yoren abandoned his mercenary band soon after and determined return this journal from where it came, back to the city of Absalom, so that this man's contributions would not be lost.
It was not an easy journey, but eventually Yoren arrived at the gates of the Grand Lodge. There he met a man who would turn out to be a member of the Silver Crusade. This man put it to Yoren that if he truly felt sorry for the ignominious death of that unlucky pathfinder in the River Kingdoms, the best way to remedy that would be to take his place, and put his sword arm to truly good use. And so Yoren chose to be an initiate in the pathfinder society, and where he once fought for gold he learned he could fight for something greater.