A third idea is that the Devil May Cry shop could somehow exist in Diagon Alley. Wizards and witches would be very confused by the strange items and weapons there. Meanwhile, Vergil could come to the wizarding world in search of some powerful magical artifacts, believing they could enhance his power, and end up getting involved in the fight against the Death Eaters.
One idea could be that Dante from Devil May Cry gets transported to the wizarding world of Harry Potter. He could mistake the wizards' magic for some kind of demonic power at first. Maybe he'd try to slay a Hippogriff thinking it was a demon, creating chaos at Hogwarts.
A crossover with the Castlevania universe would also be cool. Dante could find himself in Dracula's castle, facing off against classic Castlevania monsters while also dealing with his own demonic foes. It would be interesting to see how he interacts with the Belmonts.
One idea could be a crossover with the Bayonetta series. Dante and Bayonetta could team up to fight a common, powerful demon. Their different fighting styles would make for some epic battles and interesting interactions. For example, Dante's flashy swordplay combined with Bayonetta's acrobatic and magical combat.
One idea could be that Naruto somehow ends up in the Devil May Cry world. He might mistake some of the demons there as similar to the tailed beasts he knows. For example, he could try to 'befriend' a demon in the DMC world thinking it's like how he dealt with Kurama. Another idea is Dante teaching Naruto some swordsmanship. Dante's flashy and powerful combat style could blend well with Naruto's own energetic fighting moves.
One idea could be that Dante from Devil May Cry is somehow transported to the Marvel universe. He teams up with the Avengers, like Iron Man. Dante's unique combat style and devil - slaying abilities would be a great addition to the team. For example, he could use his Rebellion sword against powerful foes that the Avengers are having trouble with, such as Loki if he were to return in a more powerful form.
One idea could be Dante from Devil May Cry being summoned to the world of Devilman by Akira. Akira could seek Dante's help to fight against a new type of devil that is beyond his capabilities. Dante, with his arsenal of weapons and devil - slaying skills, would then team up with Akira in his devilman form to take on this new threat.
A plot could revolve around a new enemy that threatens both the world of How to Train Your Dragon (where Toothless is from) and the Devil May Cry universe. The characters from both universes have to team up. For example, Vergil might be initially skeptical of Toothless but then come to respect his power. Toothless could also interact with the different weapons and magic in the DMC world in an interesting way.
A possible plot is a magical artifact from Fairy Tail's world that is sought after by demons in Devil May Cry's universe. The Fairy Tail gang teams up with the Devil May Cry crew to protect it. The artifact might have the power to either destroy all magic or enhance it to uncontrollable levels. Dante and Natsu could have a friendly rivalry over who is stronger and who gets to fight the main villain. Another plot idea is that some of the Devil May Cry characters are sent back in time to the Fairy Tail world's past. They have to adapt to the magic - based society and help the Fairy Tail founders with a great threat that was once thought to be long forgotten.
A good crossover idea might be that some of the Devil May Cry characters get transported to the Naruto world. Dante could be mistaken for a very powerful ninja with his flashy moves. He could then team up with Naruto to fight against an enemy that is causing chaos in both the ninja world and has some connection to the demon world. Maybe they have to stop a powerful demon from taking over the bodies of the ninja.
One idea could be a story where Dante discovers a hidden demonic realm within the human world that has been influencing events without his knowledge. He has to team up with a new, inexperienced hunter to navigate this strange place.
The combination of magic systems. In Harry Potter, there's wand - based magic, spells, and potions. In Devil May Cry, there are demonic powers and cool weapons. When these two are combined in fanfiction, it creates a really unique power - up system for the characters. For example, a character might use a spell to enhance the power of a Devil May Cry - style weapon.