Devil May Cry-1
2,000 years ago, demons and humans were embroiled in a fierce war - the former for domination, and the latter for survival. In the midst of this chaos, Sparda, Legendary Dark Knight and one of the strongest and most famed of demons, turned against his brethren and sided with humanity, helping to save them and defeating the Demon King Mundus. The war ultimately ended when Sparda sealed the gateway between the human and demon worlds, along with his blade and the majority of his power, away in a demonic tower, quietly retiring to the human world.
In the aftermath of this, Sparda eventually met and married a human woman named Eva, would eventually bore his two sons - twins - Dante and Vergil. However, their life together would end up being short as Mundus, vengeful for Sparda's betrayal and defeat of him, had finally succeeded in seeping through the barrier between worlds just enough to send his demons after Sparda's family. Eva was killed and murdered before her children's own eyes, and the two were separated as their father went missing, somehow dying himself during that time.
Nowadays, the time of peace the world has lived in is occasionally broken by small outbreaks of demon activity. As a result, demon-hunting has become a common sight in some places of the world - and one such demon hunter is Sparda's son Dante, while his brother Vergil has become something of an aristocrat obsessed with harnessing his father's power for his own.
A short time ago, Vergil, with the help of a man named Arkham, succeeded in resurrecting his father Sparda's stronghold tower to open the gates between the human and demon worlds. Ultimately, Vergil is defeated by Dante and stays in the demon world - his father's home - becoming trapped there when he prevents Dante from saving him. Now that the chaos has settled somewhat, the new hurdle of unification has caused a spike in activity among demons - and changed the course of what this timeline's history was to be...