Kain is the brother of Marie Heinlein, Geese Howard's late wife and Rock Howard's mother. Unlike his sister, he faced a childhood of poverty whilst in the slums. Grant, known then as Abel Cameron, watched over him as his fatherly figure. Nineteen years before the game begins, Kain, after witnessing the violent death of a child in the streets, had enough of the slums and declared his ambitions for power. When he was eight years old, he entered a street fight and his strength was recognized by a wealthy kingpin named Don Papas. Adopted into the family thereafter, Kain eventually overthrew his benefactor and became the head honcho of the gang.