D+V requested I post here to clarify some story elements, so I figured I would drop by. Dante is my personal favourite BTW ;)
Dante & Vergil: There is still no full proof that Vergil actually died. Sure, Nero's DT comes after getting Yamato and it is Nelo Angelo, and he hasn't been seen since Dante defeated him the third time, but I have yet to see the actual proof, like his dead body. Have you guys ever heard of sealing part of your power into something else. I believe Sparda did that with Force Edge, but with all of his power. Vergil could very well have done the same thing with Yamato. When Nero damaged his arm, the order probably used Yamato to "heal/fix" his arm.
And for me, it's both Dante and Vergil for me.
Apparently in the new "History of DMC" featured in DMC4, it confirms that Vergil is in fact DEAD. Killed by Mundus following his descent to hell at DMCs end. It also says that Nelo Angelo was some kind of artifiical shell with Vergils true soul at the centre of it. Now, given that all the angellic enemies in DMC4 have Angelo in thier names, and if you check the enemy files you will see enemies like the Blanco Angelos were created from shards of a demon called "The Dark Angel" (obviously Nelo Angelo) we can tell that not only was the shell containing Vergils shell broken (likely at the end of DMC1, when Dante beat him) but that the order are closeby the whole plot thread. Given then, that Dante thinks Nero has "something different" and overwhelming evidence inidicates to me personally that Vergil is almost definitely inside Nero's arm barring serious stupidity on Capcoms part (Nero's arm features Vergils trademark colour, its larger spirit form resembles both Nelo Angelo and Vergils DT, including his Yamato sheath arm, the DBs hand design resembles Vergils DMC3 glove, the DB resonates heavily with and connects powerfully to Vergils trademark sword, the Yamato, which the DBs spirit form actually uses as ITS sword in the style Vergil used it, that it summons swords of a kind when Nero fires, and that possession by the arms power causes him to moan "power.. i need more power" the thing he supposedly heard when he first got the arm, i.e. Vergils whole motto and life reason WELL goddamn people, Vergil is in the arm. I also beleive that is the source of Nero's supposed Sparda blood (it is where Santcus stabs in that cutscene, afterall)
SO, the question now is, is the DB merely a shadow of Vergils previous self bestowed on a new character, or is it his full soul, capable of returning to power some day? I hope the latter myself, but who knows.
Carry on ;)