Medabots

Medabots is a video game franchise developed by Natsume and published by Imagineer, later adapted into a Japanese anime television series produced by TV Tokyo and NAS and animated by Bee Train. The show aired on TV Tokyo in Japan as well as Fox Kids and ABC Family in the US.

Plot
The series begins with a ten year old boy named Ikki Tenryō, who wants to become a champion of the World Robattle Tournament. However, Ikki is unable to afford a Medabot, and his parents refuse to buy him one. However, he manages to get enough money to buy an outdated model, and, with a bit of luck, he finds a medal in a river. Ikki quickly inserts it into the Medabot he purchased named Metabee. The only problem is that the medal he found gives Metabee a severe attitude problem (a problem rarely seen in a Medabot), which leads Ikki to think he is defective. However, this theory is proven wrong later in the series, as it is revealed that Metabee actually has a "rare" medal.