Bartholomew Victor was born in a place far to the south of the Realms. His parents took him to a traveling circus, and when leaving after the show, he was separated from them. For some unknown reason, his parents left without him. The Circus Folk did what they could to find the parents, but when their time in the area was over, Bart was adopted into the circus "family." He only knows his middle name - or he assumes it's his middle name - because he remembered his mother scolding him with it. He was too young to actually remember his last name, though.
He learned to play the drums and played them during circus performances. The other members tried to teach him their skills, but he wasn't naturally good enough at any of them to be interested in performing. Some members educated Bart in things like math, science, and survival skills.
When he was 22, he decided that it would be good for him to see more of the world than just the circuit his circus traveled in. He set out northward, and eventually happened upon Blackwood (because I think that was my first event as Bart). The Realms seemed like an interesting group of people, and even regular people can learn magic pretty easily, so he has decided to stick around in the Realms for a while. In between events he lives in the woods, occasionally running into other travelers and sometimes visiting a bar in a town where he can sell things he hunted/finds in the woods. It is from these people that he learns of the events that he attends.
Bart has started to miss the circus life, and one day may go back to join his family, but for now, he thinks it would be more interesting to start his own circus in the Realms.