Ottavio is a light novel-exclusive character that was the former vice-captain of Varia that plotted to overthrow Xanxus. It was he that revealed Xanxus' coup d'état plan to the Vongola Nono beforehand.
Ottavio has messy, fair hair and wears glasses. He has a thin face and wears the customary Varia coat.
Ottavio appears to be smart and deceptive, managing to betray Xanxus behind his back yet to keep a façade of loyalty. He also appears to be able to smooth-talk people, as he convinced the lower-ranked soldiers of the Italian Army to smuggle out the Italian Army's firearms.
Ottavio panics over an attack by the Italian Army, whom he had previously smuggled many firearms from, on the Varia's first job since Xanxus' unfreezing from the Vongola Nono's Zero Point Breakthrough: First Edition. Xanxus discovers Ottavio's treachery eventually and Ottavio attacks, but is overpowered by other Varia members and is killed.
- Gola Mosca: Ottavio has an older Gola Moska version that he used to battle Xanxus. It seems to be quite powerful, but had a major weak point; an easily accessible shut off button on its back.