No. 502 (伍丸弐號, Go maru ni gō) is a robot created as part of the Fuyou Project. He is the main antagonist for Fuyou Arc.
Professor Hayashi created No.502 by using his own body as a test subject at the expense of his own life. Not only did the robot inherited the professor's personality data, the rigorous experiment done also resulted in No.502 having the most resemblance to that of a real human being and was highly intelligent.
No. 502 has yellow blonde hair and pale skin. His brown eyes turned red when activating his abilities. He is most often seen wearing a suit vest with black tie.
Like a robot, No. 502 does not appear to have any emotion. He also seemed to be ruthless, killing Professor Meguro and ordering the deaths of the lab personnels without any hesitation after taking over the lab. He was also manipulative.
Strength and Abilities
No. 502 has the ability to regenerate itself regardless of the damages he suffers as long as the core within his body remain intact. With his core diameter at less than one micron, it is extremely hard to pin-point and destroy.
His arms can turn into long-range sharp weapons which can be manipulated at will, and its eyes have the ability to track and analyse moving targets.
No. 502 first appeared with Professor Meguro and No. 305 outside the Yorozuya office in an attempt to retrieve the 'Seed' that was planted in Tama's head. They gave chase after realising the trio had escaped with it. The robot then ambushed Shinpachi when he was on his way to Gengai's together with Tama's head, successfully capturing the two of them.
Through a footage that was captured by Tama, it showed that No. 502 was in fact the professor himself when the man morphed into the robot's appearance at the end of it. At the same time, the robot kills Professor Meguro and the other personnels after taking over the lab. It was revealed that although No. 502 contained Professor Hayashi's personality data, a data degradation resulted in a change of personality. He had made use of Professor Meguro to bring all maidroids in Edo into one location in order to stage a rebellion. Shortly after, he appeared on screen to declare his intent to take over the humans in Edo.
No. 502 explained to the captured Shinpachi that, although he understood that it was impossible to revive his daughter despite all the research, the first robot he has created has proven otherwise. He believes that Tama was the reincarnation of Fuyou, and that his ultimate plan was to turn Edo into a place where only the friends she like best will be around so as. His speech was interrupted by Gintoki and Tama, who arrived at the Terminal to stop him. Angered by Tama's failure in obeying commands, he attempts to destroy her during their fight but was stopped by Gintoki's intervention. The latter tried to destroy the robot but to no avail; As long as the core remain intact, No. 502 can regenerate himself regardless of the damages suffered.
He was eventually destroyed after Gintoki shoved him into the Terminal core that contained Edo's energy using his bokuto, with the help of Shinpachi, Kagura, Gengai and Tama.