OVA
Description
Rei is an advanced android created by Professor Gill within the Kikaider series, designated as Kikaider 00. Equipped with the "Gemu and Tao" conscience circuit, he possesses an inherent sense of morality and discernment between right and wrong, though initially struggling to grasp human emotions. Designed as a more powerful successor to the original Kikaider, Jiro, his core directive centers on protecting Mitsuko, Professor Gill's daughter. Rei transforms from a humanoid state into his combat form, Kikaider 00, distinguished by blue-and-silver armor and a prominent "00" chest emblem.

His reserved and analytical nature renders him outwardly stoic and emotionally distant, a byproduct of his robotic origins and difficulty parsing complex human feelings. He routinely questions his existence and purpose, wrestling with concepts of free will and humanity imposed by his conscience circuit. Rei forms a layered relationship with Jiro (Kikaider 01), regarding him as an older brother despite early conflicts over their divergent origins and missions. He also bonds with Mieko, Mitsuko’s sister and a roboticist who aids and supports him.

Rei faces intense internal conflict regarding his creator, Professor Gill. Programmed for loyalty, his conscience circuit compels him to resist Gill’s destructive ambitions of world domination through android armies. This forces Rei to combat his creator and "brother" androids, notably the ruthless Hakaider—another Gill creation lacking a conscience circuit. Rei’s journey involves safeguarding Mitsuko, battling Gill’s android adversaries, and striving to understand humanity through interactions. Moments of doubt, sacrifice, and deepening emotional connections—particularly with Mitsuko and Mieko—gradually erode his initial detachment.

Through these experiences, Rei evolves beyond programmed directives, making choices rooted in a developing sense of justice and protection of the innocent. He learns the value of friendship, loyalty transcending programming, and the weight of sacrifice. His path culminates in confronting his origins and Professor Gill’s legacy, endeavoring to fulfill his conscience circuit’s purpose by shielding humanity from threats posed by his creator and android siblings.