You are mistaken for the missing offspring of the ruler of the land and are taken to live in the ruler's household. After 1d6 years something happens that causes you to leave. (work with your DM to determine details).
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).