Not much is known about Diabolos' personality, as he only made a cameo in the show so far.
Diabolos appears to be extremely powerful, as he seemed to defeat Cure Ciel with ease.
Diabolos appeared as a shadowed figure, but his red eyes were seen glowing as he took Cure Ciel away.
Diabolos makes a cameo appearance in Episode 1, when he appeared as the fairies were talking to Cure Ciel. The fairies quickly flew away, and Diabolos picked up the defeated Cure and disappeared.
Diabolos is a Greek mythological name meaning "slanderer or accuser". According to the Bible, Satan's tile is Diabolos.
- Diabolos shares his voice actor with Mucardia.