So, DMC got a important element of the saga dead at the very first game; for getting Vergil again in game they needed to make a prequel; now they invented Nero to replace Dante because Dante is now too old and they forced Nero down our throats making him Vergil's child, in a way they are unwilling to explain, but Nero lacks twin's charisma.ok. so here is a concrete statement that vergil is dead.
during development of dmc3, before they decided on making it a prequel the writter was considering making the story take place in an alternate dimension since "vergil been alive clashed with the events of dmc1." this is from the official art book and it comes from that bingo guy who wrote the scenario for the game. he also mentioned taking to kamiya about it since it would clash with the events of dmc1 and kamiya responded with basically saying that as long as they don't say it out loud but make it obvious that it's an alternate dimension they could pull it off. then they went with prequel.
Definitively DMC story is garbage at this moment, it's a total mess!
Ok, mates, so this meaning to have Vergil we have two options: or they go with a DmC sequel ( where Vergil didn't die or he was resurrected or they make a total rewrite of the story.
No more prequels, since it keeps the story from progressing.