Miles

He isAllan andEriah's classmate. He's known as the coolest guy in the school; every girl wants to date him. Miles acts like a gentleman and is extremely kind. Teachers love him, girls swoon whenever he's nearby, and a lot of guys are jealous of all the attention he gets. 

He's currently dating Cass, but only because his father said that it would improve their family's reputation. 

He wears a ring that is possessed by a demon, and it activates whenever the demon, named Lhag, is hungry for souls. When the ring is fully activated, Miles loses control of his body and goes on a killing spree. His head becomes that of a stuffed rabbit that cries blood. 

The weapons that the demon uses are a candle stick and a rose, which have the ability to increase its length. The candlestick is used for stabbing, trapping and beating up people, and the rose is used for strangling.

Once the ring is worn, it cannot be removed up until the holder is dead.

The reason why Miles agreed to use the ring was because his family was brutally murdered, and the demon of the ring promised him that he will grant him a better life and the capability to exact revenge on the killer. Miles, who was only 13 at that time, had no idea that the rabbit demon was the one responsible for the death of his family, so in a blind rage, he accepted the deal. In just a month, he was adopted by an extremely wealthy family and became an heir to a well known company. 

The necklace he wears belonged to his little brother, and it is what keeps him sane despite the soul-eating demon he wears everyday. 

Both Allan and Memo are aware of the demon, and the demon (but not Milles) is aware of them, and they try to avoid clashing with each other because it would mean that things would get pretty messy in the school.