To be honest I was surprised that no DoomxDevil May Cry crossover had been made yet. That's why I am putting this up. I would do it, but my knowledge on Devil May Cry lore is decent at best, that and I don't have enough time to focus on another story. Anyone can do the challenge but there are rules:
Doom Slayer's background: Stays the same.
Dante: When he meets Dante, naturally Doom Slayer will first try to kill him since he's part demon.
VEGA: He should also be there. He could be downloaded into the Praetor Suit.
Sparda the Wretch: The two fought side by side together once against the demons. That would convince Doom Slayer not to kill Dante or Nero, the latter being Sparda's grandson. He could also be the Wretch, inspired by the Doom Slayer to fight against his Demon kin.
Doom 3: I feel like some elements from Doom 3 could be in it. The Doom Slayer could be depicted as the Martian Hero, having helped the Martians. And remember, the Soul Cube was found Doom 2016, so you could have that in the story too.
Demons: Along with the demons from Doom 2016 and the Devil May Cry series, you can include the ones from Doom 3 and the ones shown in Doom Eternal and the other Doom games too. Add in more fodder for Doom Slayer to kill.
If you're interested, leave either a review or PM me. I hope to see some stories soon.