Charlie (called Fukutsuru in the Japanese version) is a character from Medabots Spirits.
In the anime
Charlie looked like a suspicious character when he first appeared, using a Kilobot called Tricerapotts. He then appeared even more suspicious when he lost with barely any resistance, making Ikki think that there is a trap waiting for him.
Charlie is then later revealed to be a Medabot researcher who offered Nae a summer internship stint. He is also revealed to be a skilled Medafighter, challenging Ikki to another Robattle with his Medabot, King Tank. Despite matching Ikki and Metabee in the Robattle, Charlie again conceded the match cheaply when King Tank ran out of battery.