Oh yes, I like it! I thought of similar scenarios after the E3 trailer. :o
(I also had the idea of V being some regular guy, who is instructed by Vergil from behind, but that's not usable anymore.)
I'm still struggeling with lots of things, but for now I'm going with this background:
At the end of DMC1 the Nelo Angelo armor explodes and the amulet's chain breaks. That's what Dante sees and thinks him dead. But his real body lands somewhere in the debris and is washed into the sea when the island crumbles. He is washed ashore somewhere after some time, barely alive.
Although Mundus is sealed again, his old curse isn't gone entierly. Vergil has no memory of nothing, just wandering around half dead and tortured by nightmares. Over years he starts to remember things. He then comes close to Fortuna by chance (prequel novel says, Yamato was washed ashore there. So it should be not too far away from Mallet Island, and Vergil could end up in that region as well.) and start to sense Yamato. He observes Nero for a bit, he has no idea what's really going on, and then just walks in and takes back what is his.
Now the sword gives him a lot of memories back the good but also the bad ones. The corruption eats further away on him as well. He goes back home to die where Eva once lost her life for them.
He stabs himself with Yamato to silence Mundus's corruption, to get it out of his body. He can't stand the voices in his head anymore. Just make it stop, even if it means to die. He didn't expect to separate himself like that.
Now his remaining self needs to take actions against that demon part of him, that is still corrupted by Mundus. So he seeks Dante's help.
I'm not sure if he hides his indentity or reveals himself. I'm leaning more towards hiding, because they act so distant in the game, it kinda hurts. (One thing why I struggle so hard with thinking Dante knew the whole time V is also Vergil. He is so mad and pissed at him. :/)
V tells Dante about corrupted Vergil-Urizen, who completely lost his mind to ensure, Dante is ready to kill his brother. Dante uses Jackpot to test if it really is Vergil, like he was told and maybe, how far his mind is really gone. (But I still have to ponder on Dante's hostile actions in the game in general.)
And then I would throw all this "mother abandoned me", "what if we were swapped" and "look, a son!" stuff out.
Also still working on what V and merged Vergil are really after. And how did V know about his demon side using that tree? How did he find Morrison? (Why not go directly to Dante?)
