Speedemountain first appears in EP119 where he is the host of the Yo-1 Grand Prix. He says he is pleased Nate could make it and offers him an entry to join the race. Nate accepts the offer. In a flash, Speedemountain makes all competitors' cars appear along with changing Nate into race clothes. Speedemountain motivates Nate, Whisper, and Jibanyan as the race preparations are complete. After Nate, Whisper, and Jibanyan win the race, Speedemountain gives Nate is medal.
Maunten's design is based on a pun on maunten (Japanese: 魔運転,"demonic driving") and the English mountain.
Speedemountain combines the words speed demon and mountain.