Damn where to start, ah who cares. 2000 years ago, the demon world was connected to the human world, during that time demons attacked humans everyday. Sooner or later a war broke out between the Humans and Demons, among the humans was a demon. The demon who sided with the humans was none other than the legendary Dark Knight, Sparda.
Sparda, along with his students, Baul and Modeus, fought against their own kind. However, Sparda knew he couldn't defeat every demon in the demon world, so he decided to close the connection between the two worlds. But by closing the door to the demon realm, he sealed his own powers as well, banishing his sword, Force Edge, deep into the demon world. After closing the Demon Realm to the Human World, Sparda would become a traitor to his kind but a savior to the humans.
Sparda then wandered around in the human world, looking for demons that escaped before he sealed the door. As he began his hunt, he met a devil hunter, a woman named Eva. She knew he was Sparda, the legendary Dark Knight, and fell in love with him, due to the stories she heard about when she was little. It may have been an awkward relationship but they still loved each other. A few years later, Eva and Sparda had a child but it wasn't one, they had twins, named Dante and Vergil. When the Sparda twins where young, Sparda mysteriously passed away, disappearing from human history but not the demon's. But this is where my story begins...
Devil May Cry, The Devil Hunting Organization
Hunt down all sorts of demons, fallen angels, and devils along with the odd jobs