Gio is a dragon from the ISDA who is assigned to be Kazuki Tachibana's "partner" after Kazuki successfully resonated with Gio's dragon egg form. However, despite being Kazuki's partner, Gio does not take orders from him, showing more concern for Toa, whom he states he was born to protect. He is very adept in using a sword while in his Communicator form.

His name is derived from his code-number, "G10", which Kazuki misread as "Gio."