Wild carnivorous beasts invade the character's camp. During the attack, the character finds that he has the innate ability to command wild beasts (not monsters) to do his will (so long as it does not seriously risk the animals' lives).
Rebellion: As an adolescent you joined a rebellion against the local ruler, if successful you are outlawed, if it failed you escape, with only friends and family knowing your involvement. (Work with your DM to detirmine the details)
Approaching adulthood you experience wanderlust and decide to travel, roll 1d6 to detirmine years spent travelling and think about where your character might have gone. (work with your DM to determine details)