Evan Smoak is a helper.
For many years, too many for his conscience, he was an agent for the government working for an organization with no apparent name comprised of agents with no real past. His name was taken from him though if he were honest with himself he could not say it had ever been his real name. He was an orphan from before he could remember so whatever he was called, it might have been given to him at birth or sometime later. After he was taken from the orphanage at age twelve, he was asked to create a new name. He accepts the suggestion given him and he becomes Evan Smoak. More importantly for the group who trained and then employed him, he was Orphan X.
Through his teen years, learned all that his instructors could teach about pain - giving it and receiving it. He learned how to work through the agony and despite agony and he learned that if he could do it, others could, too. He discovered that many others had been taken down at the last moment by a defeated foe. He learned not to give them the chance.
It was a man named Jack who took him from the orphanage and started his training. It was Jack who was his instructor in many things and his conduit to other teachers for even more. It was Jack who became a cold father figure as well as nurse when injured. It was Jack who taught him the numerous Commandments that would help him survive when training led to doing. First and foremost of these rules was "Assume Nothing". It would save him more than once and chastise him when he forgot it. It became a vital part of his entire way of life.
When his training was over, if it ever really was, he went into the field and used those skills he had so dearly paid to acquire and he caused a good number of bad people to cease breathing forever. After a time, though, no matter how bad the people were, what he was doing ate enough of him away that he knew he needed to stop. More than that, he needed to give back. Not, of course, to those he killed. They deserved it. And not to himself for he had no self-pity. To others.
So he left his work and became the Nowhere Man, a nickname given because he came from nowhere, did what needed doing, and went back there. He did not ask for money or glory or even thanks. He just came to those who were beyond help from others and did what he could to save them and then left.
It might have been better for the Orphan program if they had just let him go.