In the story mode, you eventually get to Dante, because Dante realizes you have his brother's sword, and in fighting you, he also realizes you're his son (Vergil's). In here, if you played normal mode, the boss seemed easy. Which once again: Understandable.I don't get this statement.
That means Dante in there is a story boss. Not a filler, not a challenging boss, but a boss created purely for story purposes. Nothing more, nothing less.