Loveless, in any incarnation, begins when a big brother named Seimei tells his little brother Ritsuka his true name: Beloved. Never mind that he didn't know what that meant -- true name -- it was still an exciting secret about his brother who he adored so much.

A week later, his brother is murdered. Their already unstable mother, Misaki, becomes even more vengeful and angry at Ritsuka, who is an amnesiac and can't remember what life was like before two years ago. With no one to stick up for him anymore, not even his father, Ritsuka must contend with a violent, disturbed woman every day.

On his first day at his new school, twelve year old Ritsuka makes friends with a bubbly girl called Yuiko. He reluctantly lets her go with him to the library, but she tactlessly points out that he sometimes acts like he has a split personality. This hit such a sore spot that he tearfully runs away, and as he's passing the gate, a hand reaches out and grips his arm. "What's wrong, Ritsuka? Why are you crying?" he asks. Ritsuka asks the man who he is, and the man is pretty surprised that Ritsuka doesn't know. Didn't Seimei tell him? The man introduces himself as Agatsuma Soubi, a fighter. He was Seimei's, but now he is Ritsuka's.