>>4152812At one time, 2 was going to be the 'finale' of the series with Dante being trapped in hell. The story of 2 is actually about the last Hell Gate in existence being closed (those things Dante and Nero fought to close in DMC4).
At some point I guess they figured that Uncle Dante simply coming and going from Hell any time he feels like it is way more cool and unique to canon than 2 where it's implied he's trapped there forever because that limits the number of games and also means Uncle Dante would be younger than Emo Dante.
Which makes more sense, 2 isn't very beloved anyway for a number of reasons and you can see the age in Uncle Dante compared to Emo Dante. That said, I still like Emo Dante's outfit better.
