Ok, what I am about to say is just part fact and part speculation, nothing else. It did say Nero's right shoulder was injured so i'm guessing it was an infection or something that spread to his whole arm. Nero does seem to have some tie to Vergil. Berial said "You are just like him." He could've meant Vergil then again both Dante and Sparda have been to Hell also, so it could mean either three. The DMC recap explained some things that were not known before. It said that Vergil's soul, NOT body, was in Nelo Angelo, meaning he is basically dead and if he comes back it will most likely be in another form. Some say Vergil was the Despair Embodied from DMC2, but that is merely speculation. Dante has absolutely NO love relationship with either Trish or Lady. It clearly explained he and Lady have a friend-like relationship (her giving him jobs and him completing them) and I don't know about any of you, but I wouldn't like anyone that looked identical to my mom sexually so that rules Trish out also. My guess is that since Sparda's devil form was put in his sword so was Vergil's. That would explain Nero having a DT in Yamato. I probably haven't answered much I just wanted to share my opinion and shed some light on false rumors. The three biggest questions I want answered are:
1. How could Sanctus use Sparda? I thought you needed to be a Son of Sparda to use it
2. How could Nero defeat Sparda with Yamato? If Sparda could defeat Mundus and Vergil couldn't it doesn't seem right that Vergil could defeat Sparda
3. And finally, who, what, when, where, how: devil bringer.
Whoever read all this thanks I know I went on sort of a rant lol.