Considering Nero's actually more resembles one of the Order Knights than Vergil *points at the hood and design structure, which seesm to form to the vest and coat* THat's a good indication his DT is NOT supposed to be Vergil's. We saw in DMC3 that he and Dante do carry commonalities in their Dt forms...I'm not seeing much Nero's had in common with either of them, same the Yamato arm sheath(and that's a Yamato effect.) I still say his DT Aura is influenced by the Devil Arm he's using, like DMC3 and DMC1 Dante, so...imagine a Rebellion fueled Nero DT Aura...or maybe even a Sparda fueled one.