Main characters of "Devil May Cry" - Vergil

Vergil is my personal favorite, that's why I mention him last.
Vergil is Dante's elder identical twin brother, though the two are near-polar opposites; unlike Dante, Vergil embraces his demonic heritage. He is a chief antagonist in Devil May Cry 3 as well as a playable character in the game's Special Edition. After he is betrayed by Arkham at the end of the game's second act (the end of mission 13), he temporarily teams up with Dante near the end, before reverting to his villain role. Throughout the game, Vergil seeks to undo the seal of Sparda hidden within the Demonic Domain, and claim the entirety of their father's power for his own, regardless of the effects this will have on the human world. To do so he needed Dante's half of their mother's amulet, so he lured his brother out with the intent of taking it by force. His dialogue at the end of mission 8 indicates that he seeks this power to compensate for being unable to save their mother . Vergil battles Dante three times in the Devil May Cry 3 storyline. Their first battle is on the highest level of Temen-Ni-Gru, where Dante is soundly defeated by Vergil, who then takes Dante's amulet. Their second battle is at the bottom of the tower, where the twins battle to a draw before their battle is interrupted. Their final battle is near the entrance to the demon realm, where Vergil is finally defeated. While Dante escapes back to the human world, Vergil chooses to stay behind. Should the player be able to defeat at least 100 demons before the credits finish, the player is shown a cutscene with Vergil rising to his feet in a lake of blood, and looking into the sky to see three large glowing orbs in the sky – Mundus as he first appeared in Devil May Cry. Vergil decides that if his father was able to defeat Mundus he can too, and then charges at the orbs with his sword ready. Vergil survives his encounter with Mundus, but becomes enslaved and apparently brainwashed. In the first game, he appears as a demonic dark knight, called Nelo Angelo (a mistranslation of Nero Angelo). Dante encounters Nelo Angelo three times in Devil May Cry, and each time Nelo Angelo sees Dante's half of the amulet, he flees the battle. In their final encounter, Nelo Angelo uncovers his face to reveal that he is Vergil. In the end Nelo Angelo appears to explode, leaving his half of the amulet behind.

Main characters of "Devil May Cry" - Sparda

In the Devil May Cry universe, Sparda is a demon that rebelled against his own kind for the sake of the human world two thousand years prior to the events of Devil May Cry. He defeated countless demons and their Emperor, Mundus, before sealing the gateway to the demon world, sacrificing both his own blood and that of a mortal priestess. These actions made him a legend in the human world, gaining him the moniker, The Legendary Dark Knight Sparda though they also incurred a notorious reputation amongst demons, many of which were defeated during his rebellion.
After his death, most of Sparda's power was concealed in the demon realm, sealed inside his sword- the Sparda/Force Edge, and was only accessible with an amulet he took with him into the human world. This amulet, which can be separated into two parts, was also one of the keys needed to unlock the portal. All its abilities are deactivated if the halves are separated. Near the end of his life, Sparda settled with a human wife, Eva, and fathered twin sons, Dante and Vergil. He gave his amulet to Eva as a gift which she in turn later separated and passed to her sons. Both Vergil and Dante received a powerful, enchanted sword from their father, Rebellion to Dante and Yamato to Vergil. In Devil May Cry 4 a cult organization called the Order of the Sword cast Sparda as a god-figure who had ruled over their capital, Fortuna. While it's unknown as to how he died, Dante understands that among the people there is a lot of confusion surrounding Sparda and who he truly was.