The Reaping (2007)

Loren is an angel that's bringing the Biblical plagues as punishment to the town because pretty much all the people of the town are part of a Satanic cult that sacrifices children (except the first born) as part of selective breeding. Costigan (Stephen Rea) tells Katherine (Hilary Swank) that if a first born child of the Satanic group dies, then the second born child will be "reborn with the eyes of the Devil." Katherine is about to kill Loren and sees what happened earlier (when Ben and Katherine were investigating the first plague): Loren was going to be killed by her brother but he died when he stabbed her. Also, Doug killed Ben and made it look like Loren did it to motivate Katherine to kill her. Before the last plague hits the town, Doug asks Katherine to kill Loren so the plagues stop but she refuses. The plague that kills first born children kills everyone in the town because they are all first born children. The next day, Loren and Katherine leave town and Loren asks "What about your son? We'll take care of him, right?" indicating that Loren and Doug did have sex and it wasn't a dream (as seen previously in the movie). Since Katherine's future son is her second child and her first child died (years ago in Africa) then her son will be reborn with the eyes of the Devil...

Alex