Luka Mizuma is a supporting character in Special 7: Special Crime Investigation Unit. He was a police detective and a former colleague of Shiori Ichinose, as well as the older brother of Kujaku Nijo. By the time of the series' main events, Luka has already died, and a tomb has been erected in his memory. During his lifetime, he was known among his peers for his strong sense of justice and his dedication to his work. He played a pivotal role in the backstory as the detective who saved Seiji Nanatsuki, the protagonist, on a prior occasion. However, it is later revealed that Luka was also an underling of the antagonist Warlock, indicating a complex and morally ambiguous history. His relationship with his brother Kujaku is a significant emotional thread, and his death and past actions continue to influence the motivations and development of other characters, particularly Kujaku and Shiori. Luka’s abilities as a detective were evidently respected, though specific supernatural or combat skills are not prominently detailed; his legacy is defined more by his personal connections and the weight of his choices.