Theories

look a little deeper

Again, these are my opinions.

† Goals - Why does he feel the need to acquire more power?
† Dante + Vergil = Sparda - A small Equation.
† Wing?! - I saw a wing. I explain it here.
† Lost soul - Vergil / Nelo Angelo as a puppet (more than he already is).
† Devil May Cry 4 theory - What Devil May Cry 4 hints at.