Tao (Kor. 타오) is a 24-year-old young man who possesses a genius-level intellect in computer programming and other technological fields. He was one of the less cold-hearted members of the DA-5 group, made by Dr. Iris, and is yet another a modified human. He is currently residing with Takeo and M-21 in Frankenstein's residence and is also working as a security guard in Ye Ran High School. He is "Number One" of the RK-4, or 4 Raiziel Knights, which is a group he formed by himself. Within the RK-4 he is known to be the most charismatic and vocal, actively supporting and leading his collegues.