Android Kikaider is a manga series by Shotaro Ishinomori serialized in Weekly Shonen Sunday from 1972-1974. It was released alongside the tokusatsu series Android Kikaider and Kikaider 01 following similar yet parallel plots.
Dr. Hiroshi Komyoji had completed a robot that would stand up to the heinous Professor Gill and DARK through a special Conscience Circuit. However, the Conscience Circuit was left incomplete as Dr. Komyoji was attacked. The robot was ejected and given the name Jiro also known as Kikaider. Taken in by Dr. Komyoji's children, Mitsuko and Masaru, Jiro fights against the robots sent by DARK while learning they were created by Dr. Komyoji as well. Eventually, he encounters the cyborg with Dr. Komyoji's brain Saburo also known as Hakaider. Jiro is brought to DARK's hideout where he manages to get their scientists to reintegrate Dr. Komyoji's brain back into his body while making the base blow up.
But Professor Gill and his scientists survived and became the Hakaider Squad. With the odds against Jiro, Dr. Komyoji directs him to a temple where Jiro meets his 'older brother' Ichiro a.k.a. Kikaider 01. The Kikaider brothers encounter a nurse named Rieko and Professor Gill's son Akira who has the plans for Gill's ultimate weapon along with his sister Rumi. They are being chased by both Hakaider and the mysterious SHADOW. Jiro and Ichiro fight against SHADOW eventually getting help from the android Mieko a.k.a. Bijinder and an android Jiro made called Rei. At the end, Hakaider takes the children and completes his weapon that wipes out SHADOW and later takes control of Jiro's group. Jiro however was not affected like the others and destroys his former friends and Hakaider, rescuing the children and walking away unhappy with the results