Yoshinobu Izaki

During his childhood, Izaki was raised by an emotionally unstable and controlling mother after his father abandoned the family to run away with one of his students. His mother developed a deep hatred toward female high school students, whom she blamed for destroying their family, and became increasingly possessive of her son.

As Izaki grew older, his mother's obsessive behavior continued to dominate his life, leaving him with conflicting feelings of love, resentment, and anger. Following her suicide, he developed a fixation on breast milk, believing it could provide the comfort he had lost. His unresolved resentment toward his mother and hatred of female high school students eventually became central to his crimes.