Meguro Masaki was a murderous mercenary working under Hayami Katsumasa. Under Hayami's orders, he became the affiliated fighter for Umiichi Securities during the Kengan Annihilation Tournament.

Meguro could be described as a clinically insane person who had severe sadistic, masochistic and psychopathic tendencies. He greatly enjoyed the act of murder and constantly uttered to himself how he should go about the act, always wondering whether the kill would be better than the murder of his father. His sheer ecstasy when fighting and killing lead him to cry blood, earning him the nickname the "Crying Man". He was also incredibly impatient, which was a weakness of his.