Sorry to but in here like this but i had to give my 2 cents
Well Nero in fact has a blood connection with Dante, even if it's just by the father side (Sparda i think?) because as said by Sanctus ( I needed someone of Sparda's Bloodline to complete the heart of the Savior, i intended to use Dante, but you will do just right.) Still this is countered by Sanctus by saying (how fortunate it is to find Sparda's Gift? outside Dante's Bloodline) in the relationship with the Devil Bringer, if i remember correctly there was an demonic invasion in Fortuna, Nero was already present there and i believe that he was without the Devil Bringer, it was because of that invasion (warning speculation here) that the militant section of the Order Of the Sword was created. It is plausible that Nero Angelo Soul had escaped it's captivity in hell, during that invasion (maybe the invasion was caused by Berial sudden rose of power in Hades
![Er... what? o_O o_O](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
), and found a perfect host in Nero, who already possessed demonic blood, and thus it awoken the Blood's power by demanding "more power" and that awakening gave rose to the Devil Bringer.
Well sorry for that really long and boring post but i had to but in
![Stick out tongue :p :p](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
.
On a side note i really liked to have a Devil Bringer for myself it would save me lots of space in my house :lol: