Kohei Kakihara  

, 柿島耕平

A professor who served as Nijū Mensōs supervisor during his time as a scientist. Despite cautioning Chiko against trusting Nijū Mensō, he is deeply fixated on acquiring Nijū Mensōs research legacy and achieving the "fourth state of water". He disregards any consequences and believes that the power of the fourth state will revolutionize the world, regardless of its destructive nature. Additionally, he utilized Seiji Tamiyas research to develop advanced cybernetic bodies for himself and others, eventually transforming his appearance into that of Nijū Mensō. Originally known as Nijū Mensō, Kakihara's name became synonymous with the young scientist while his own identity was eclipsed by Nijū Mensōs actions. He is morally bankrupt and driven solely by the desire to complete the research that Nijū Mensō conducted before World War II, which he believes was unfairly withheld from him and resulted in countless deaths.