Yes, Vergil is still around, but this doesnt mean other possibilities can be ruled out of the situation. Neros arm had nothing to do with Vergil before, it seemed like a manifestation of his own power or a natural occurance. If however he did posess Neros arm, then Vergil would have done it already and consumed his body, along with hurting Nero not helping him.Neros arm glows different colours in different situations, angry red, blue normal and most amazing bright, illuminous yellow when touched by Kyrie. I doubt if it were Nero then these odd colours wouldnt take place on an evil arm by Vergil, especially love if anything, Nero seems in control.
However, another point. When Nero blacked out, he envisioned Kyrie being taken and hurt, this over-whelmed him with anger, thus only then reviving Yamato into Neros hand. If Yamato was truely designed for his hand, it would have flown into Neros posession ages before when confronting Agnus. Also, another point, as is previous installments in the series, different DT forms are seen. Lets look at it this way... Maybe Nero's DT is simply a result of Yamato and has absolutely nothing to do with Vergil. Think about it like this... Vergil and Dante got their powers (or additional powers) because of the swords, Nero is simply having the same effect due to the Yamato, same as Vergil.
Who's to say that if Nero had the Rebellion that he wouldn't resemble Dante? Also remember that when Dante had the Alaster, his DT looked like Sparda. It's the Yamato not Vergil. And one more thing, just in case some says, So why didn't Dante look like Vergil's when he had the Yamato?.... Keep in mind that Dante STILL possessed the Rebellion despite having the Yamato, and that's probably why.
Neros DT could be anything from what we know.
