Vergil, son of Sparda. He is the biological twin of Dante, Son of Sparda. HE is also the demon king. He is married to Raven Lily Potter. He is very skilled with a katana blade and is the owner of the Yamato, the sword his father gave him.
He also started an organization known as The Order. This organization is/was put together to fight off the demons and specifically the demon king Mundus in Capcom's video game, DmC: Devil may Cry. In the book, DmC: Devil May Cry The Chronicles of Vergil he appears to be in love with psychic and member of The Order, Kat. Kat later betrayed not only him but the Wizard Club as she joined the Death Eaters and was killed by Raven for this betrayal shortly after.
Vergil, son of Sparda is the biological twin of Dante, yet he is known not to get along with him as Dante sees Vergil as powerhungry and heartless. In Capcom's Devil May Cry 3 they battle 3 times throughout the game in DmC: Devil May Cry Vergil decides he wants to take over everything in an attempt to "protect the humans" and as Dante once again disagrees, Vergil is a boss battle in the final level in this game.
In the DLC for DmC: Devil May Cry, Vergil's Downfall you get to see the aftermath of the fight between Dante and Vergil. He falls into Hell and fights demons and also kills two visions of Dante and Kat. He's basically gone insane. ._. He also finds his mother being attacked by a demon, this time she's real, and is heartbroken when she finds out the only reason she came was to rub it in her face that he killed "Dante". More towards the end, he fights his hollow self and he attempts to do this whole Hell thing all over.
When he comes back to the real world, demons come seemingly about to attack them. When they get close, they all reach to a halt and bow down to him.