Right that "Nelo Angelo" haha. Well to me, I think it's not THE Nelo Angelo anymore, more like a shell of its former self. I did read up on some fan theories about how the Angelos (Cavaliere) in DMC5 could absorb a powerful being i.e. Trish to power them up, meaning that might have been what happened to Vergil in the first DMC. But.... I don't think that's the case, and it's just Cavaliere Angelo's ability.
The dev team probably brought it back as a means of recurring enemies like Frosts and Blades/Assaults in DMC4. From the gameplay video, it doesn't look very powerful. A shame really. Maybe a miniboss? Or maybe just a weak mob XD