Hello. I am Barbatos, the Royal servant of Lord Diavolo. This is the Royal Academy of Diavolo. RAD is what we call it.

The student council officers are the demon brothers. There are seven of them. 

Lucifer, avatar of Pride, is the oldest. I suspect him dating Lord Diavolo.

Mammon, avatar of Greed, is the second oldest. He usually has a lot of debts with witches. He does not know math unless every number in there are numbers of Grimm.

Leviathan, avatar of Envy, is the third oldest. He is very much obsessed with anime and is a self-proclaimed 'otaku'. 

Satan, avatar of Wrath, is the fourth oldest. He is born from Lucifer's emotions. He loves books.

Asmodeus, avatar of Lust, is the fifth oldest. He loves himself more than anything and is most likely pansexual and hypersexual.

Beelzebub, avatar of Gluttony and Belphegor, avatar of Sloth are twins. Beelzebub has a black hole as a stomach, and Belphegor sleeps in the day because he stays up in the night. They are twins. However, Beelzebub is older.

Simeon and Luke are exchange students from the Celestial Realm. Simeon seems like a cult stripper and Luke acts very much like a Pomeranian, not a chihuahua.

Solomon is the exchange student from the human world. He is the most powerful sorcerer. He, in my opinion, should voice act in Yaoi.