You were killed. However, your body returns to life with two resident souls yours and that of an ancient, alien being. The other spirit awakened for a purpose, one that it keeps secret from your mind. There are occasional fights for control of your body.
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.