Toni is Vivi's demon butler who was forced to live in the human world after Vivi got bored of his life as a Demon Duke. Toni has known Vivi since they were ten demon years old, and was the first family servant to ever lecture Vivi. It was because of this that the two became close, and Vivi won't allow anyone else to serve as his butler.
Toni is a very kind person and is extremely fond of Hana. He loves cooking and tending to flowers. Since flowers die when touched by demons, Toni is forced to wear gloves (and even a paper bag over his head) when tending to them.
Toni gets a side chapter devoted to his back story in Volume 4, Chapter 18