Shinichi[]
Shinichi Mechazawa is a robot who seems to believe that he is human. He's considered one of the major characters in the series, and is often the one representing the series in case of possible cross-overs. Only a few of the main characters realize that he actually is a robot. Although Takashi Kamiyama is willing to let Shinichi be beat up so that someone can point out that he is a machine at first, they quickly become friends, and one chapter explains that the main group never tell Shinichi about his true form because it would be bullying.
Shinichi has a lot of respect from the other students because he comes with sound advice and is good at fighting. Despite this, much of his screentime is spent being destroyed and/or suffering other humiliation. Much of this humiliation happens when he attempts to be out in the open and would have been avoided if others would be able to tell the difference between him and the machines he gets mixed up with.
One time, Takashi accidentally turns him into a motorcycle. The motorcycle is able to fly and shoot rockets, and has been used by Takashi to fight crime.
He has a little brother, Beta, who he is very protective of (despite mistaking him for a beer can once) and sometimes carries around. He will lose his calm if somebody lies about Beta's whereabouts.
The manga author did note during Mechazawa's first appearance that he made the character specifically to appeal to young children.
Shinichi's voices are provided by Norio Wakamoto (anime), Jay Hickman (English dub) and Shinji Takeda (movie).
Beta[]
Beta can only say one word, "Mecharatta", but seems to have a good enough AI to communicate in other ways. When Shinichi laments having fallen in love and wishes to start his life over, Beta carries a CD with a new OS (pictured to the right) to Takashi so that he can update Shinichi, and erase all his memories and personality. He seems to not have a pain-function, but to still be able to feel embarrassed, as shown in his reaction to Akira Maeda opening his head like a can by accident.
Beta can also be used as a phone, and Akira took advantage of this to call everybody to his home after Shinichi had disappeared. How he knew the number is never found out.
Like his brother, Beta has been mistaken for something else, although his comedy is more about being crushed beneath somebody's feet than mistakes like that.
His actors are Mika Kanai (anime) and Luci Christian (English dub).