Bjorn had always been a gregarious fellow, growing up with three older brothers and three older sisters. He would spend hours trying to entertain his siblings with tales of his imagination.
As he grew up, this became his mode of interacting with people. If he could get people to laugh, he could be sure he was doing the right thing. He had no particularly useful skills beyond bringing joy to people until one fateful night of over-drinking with a gnome named snarkel.
He woke up, with no memory of losing consciousness, in a completely different part of the world with pixies swarming over him and through his stuff. He's never quite been able to get rid of them, but on the plus side, they laugh at his jokes and share their magic freely.
Someday he'd like to get home, but for now, he's happy to travel around seeking to replace despair and gloom with joy and cheer.