You have to play the Special Edition of DMC3.
Perhaps you're playing the normal one that's why you can't unlock Vergil. <^x^>lll
I thought that Nero was the main character in this one.. <x_x>
OUT OF TOPIC : sorry ... um ... i just wanted to ask since there's no DMC3 thread if anyone completed all difficulty degrees and unlocked everything in DMC3SP ? cuz i have finished "normal mode" and "hard mode" and "very hard mode" and i'm in "Dante must die mode" ... and if anyone completed any mode in Vergil (i have completed only the "normal mode") and bought every skill and item except "holy water (only 14 out of 30)" and reached about 3/4 of the bloody tower ... well did any body?