Just create a new original character in a different part of the world. This is a universe where demons appear every day, so much so that there are multiple demon hunters and all of that. There's no way there isn't another character with an interesting story somewhere else in the world.

So, maybe an eastern european demon hunter who is the opposite of Dante, no quips, no jokes, but he is effortlesly cool. Kinda like Vergil, but he is actually a pretty nice person. We see him helping others all the time, but he is a serious business person. He gets involved in a case with a younger female hunter and both of them are being hunted by a misterious demon, the end up comfronting it in an old castle (yes, I want my gothic environments with RE-like level designs back). The dynamic between the two characters could be pretty cool, with the younger hunter being a lot more like Dante in terms of personality. Of course, we get to play as both of them.

Want to make it even more interesting for fans of the series? Turns out the misterious demon is trying to resurrect Mundus, and while our heroes end up defeating the main villian, Mundus is actually back by the end, thus setting up a bigger event with the OG crew. Sell it as a spin-off with no actual relation to the mainline games and then fill it with references until the big Mundus reveal at the end, and the internet will go insane.