Why would you do that? No one ever said Nero is even remotely related to Vergil or Sparda. And having Vergil's voice INSIDE HIS HEAD kinda makes me believe, their relationship isn't based on mutual understanding OR fatherly love. It's more or less implied, that Nero got his powers after being attacked by a demon, escorting Kyrie through the woods (in the scene before he goes DT, he makes some remarks on that)
All throughout dmc 4 they say that nero has inherited the power of sparda even sanctus said so
Well, yes. But that's hardly the point now, is it? Vergil is a mentally crippled villain, no matter the justification. It's hard for me to accept this theory, because the one I have myself is pretty much engraved into my skull by now and we have no proof whatsoever to really say "Yours is right, mine is wrong" (or vice versa).
Threre's no proof to any theory on this blog and what we write comes from analyzing the plots of each game.
These are just theories that we share You dont have to accept it if you dont want to