He didn't have a traumatic childhood; he was pudgy and bookish, but fairly well-off, so he was never ostracized or abused by his peers. His parents liked him well enough and his siblings (an older and younger brother) weren't cruel. He tended more toward isolating himself from others, because he was very intelligent and didn't have the patience for dealing with them - even if he had been ostracized he wouldn't have really cared, since others' opinions haven't mattered to him since he was 10 or so. 

He had priests as tutors after it was obvious he was more intelligent than more general schooling would nurture, and preferred that - it didn't do wonders for his social skills, but socializing wasn't high on his list of priorities anyway. 

His interests turned toward magic and he started keeping a spellbook as a teenager, trying to work it out for himself from books and discussion with the priests. 

When he was 16, about to turn 17, he made a decision and told his girlfriend and family that he was joining the priesthood (priests of the Wyrn function as bureaucrat and government, but also have a few stringent vows - notably a vow of chastity). After his birthday he went into seclusion for a few years and learned, in equal parts, the arts of bureaucracy and the elemental magic of the priests. For this magic he sacrificed his ability to have a family, and with his mastery he was given an amulet that attunes him to the elements.

He'd kept growing while sequestered, and gone from an average-height, chubby teen to an absurdly tall and rather skinny young man. Since he'd never been all that interested in actually joining the ranks of the government, and one branch of magic was not enough to occupy his mind for long, shortly soon after his training was finished he moved on with a trading caravan and provided a little bodyguarding in exchange for passage that eventually got him to another temple that he had read about. 

The Sentinels of the Mind are primarily women, but they accept accomplished male wizards, and he was able to demonstrate that he qualified. Unfortunately for him this time it involved a two-year vow of silence; his temper didn't accommodate that well - and every time he broke it he had to start over. They consider there to be no better way to teach mindspeak, though, and he was able to get through it eventually. From them he learned extensive mental magic: mindspeak, self-healing, moving objects without touching them. 

The position of the Sentinels of the Mind is that to enhance the mind the body should wither. For this magic he sacrificed his good health, and with his mastery he gained true levitation. This doesn't seem like such a large thing, and there are other sects and temples whose members can lift themselves off the ground, but only the Mind's Sentinels are capable of anchoring themselves and becoming as immovable as a stone in the earth while suspended in the air. 

After his time there, he moved to the cold south to join a group known only as the Seekers - not famous for their magic, but hinted about in books and among other magic-users. The Seekers are interested in nothing more than knowledge, and have the most extensive libraries known in the world. To join them he first had to recount his life in excruciating, intimate detail and have it recorded in their histories. Their magic is referred to as 'seeing with the eyes of a god'. Not any specific god, mind, just 'a' god. They find these gods themselves and have their bodies decorated with tattoos to represent them as they gain their powers. The ultimate goal of Seekers is omniscience; they know it's an unattainable goal, but that's no reason not to strive for it. 

He considers himself a Seeker in a way he doesn't identify with his other groups, even his own homeland. He carries books to record secrets and stories, occasionally sending them back to the libraries to be sorted and archived. Now he is working as a court mage to save money to buy his way into the next sect.