Nova

Bears a contract with #13 of the Arcana - Death and the Captain of the Holy Grail. Felicitá's childhood friend and cousin. He calls her by her first name. His Arcana sign is on the back of his neck and his power is to put people in sleep. He is talented despite his young age and because of this, stands at the top of his division.

Spoiler

He put his parents into a deep eternal sleep when he overheard them plotting rebellion against Mondo, so Nova would be the leader instead. But later, with the help of Felicitá and also Mondo, he's able to wake them up again.