The third game seems to have shamelessly ripped off of the novels anyway, so it might as well go all the way. Compare
Vergil, Dante's twin brother who is inexplicably alive when the existing canon had him "presumed dead", opening up the Demon World-- if Note of Naught is to be believed, this includes turning all the residents of the city into demons.
vs.
Gilver, revealed to be Dante's twin brother who is inexplicably alive when the existing canon had him "presumed dead" (or kidnapped by Mundus?), opening up the Demon World and actually turning all of the residents of the city into demons. Gilver was much more personal about his terribleness, though. But that comes from the novel being able to fit more characters that Dante had relationships with.
Lady, a human who is a demon huntress, who knows about Sparda, who wields a large weapon (a rocket launcher), whose father delved too deeply into the occult and became a demon because of it, who has a scar resulting from her encounter with her demonic father (implied), with a backstory involving a dead mother, and the additional detail of her father having a scar on his collar/neck that pulsates near demonic activity.
vs.
Beryl, a human who is a demon huntress, who knows about Sparda, who wields a large weapon (a Spiral-like rifle), whose father delved too deeply into the occult and became a demon because of it, who has a scar resulting from her encounter with her demonic father (stated), with a backstory involving a dead mother, and the additional detail of Beryl having a scar on her collar/neck that pulsates near demonic activity (the Beastheads specifically).
The actual locations and general plot are different but the scenario writers seemed "inspired" by the novels a bit too damn much.