Kikaider's design is based on a model of the human body. The blue body color symbolizes the heart of justice, while the red symbolizes the heart of evil, representing an "imperfect conscience. "Even before the show aired, there was some criticism in the industry that the design was asymmetrical and that the parts of the body that were transparent were creepy, but Ishimori, who was in charge of the original work and design, later said, "I am proud to say that this is one of my best designs.