I'd like to see the following:-
The world gets rebuilt quite quickly with Kat and Dante's assistance. The demons are all vanquished and humanity regains its freedom. Dante and Kat then plan to ride off into the sunset together. A few months later, the countries of the world plan their first free national elections for a while, Kat and Dante look on in mild satisfaction at a job well done. However, a few weeks into the campaign, Kat goes missing. Dante, obviously upset, begins to hit the bottle.
Three weeks later, and only a few days before the election, the main narrative itself begins. Dante receives a visitor at his apartment. The man says that he is NSA and that he might have intelligence on the whereabouts of Kat. The 'might' part of the sentence makes Dante rather irate. However, the NSA man is able to calm Dante down by offering to show him what he has. A small file containing six photos. The NSA man remarks that not only is the man who took these photos, missing but disappeared whilst investigating a lead on one of the three main candidates for the election.
The photos show the candidate getting out of the back of his car to meet supporters. He shakes hands with an unknown individual. However, this man is some sort of discomfort. Someone accidentally knocks into him from behind, and he looks in agony, clutching his chest. The final shot is of a head of a young girl poking her head out of the car door to make sure he is alright.
It all goes downhill from there.