Mandy grew up as the master of Grim Reaper along with her best friend Billy. They went on many adventures together until Mandy noticed she was immortal because of her friendship with Grim. After Billy's death she let Grim go and they occasionally met. Grim fell in love with her and proposed to her. Mandy agreed and became along with Grim the ruler of Castle of Grim. She has two children. Grim Jr. through an abortion, and Minimandy through an affair with Nergal Jr.. She is considered the most heartless being in the Underworld.