Hostile encounter. Followers of a god are persecuting unbelievers, you had a direct or indirect interaction with them. (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).
During your early adulthood you saved someone's life. This person becomes your companion. (work with your DM to determine details) Roll 1d10 on a 9-10 your companion falls in love with you.