Just finished Epiphany; loved it to bits. But like other players, a few of the loose threads did nag at me slightly. I have read the developer explanations for why some of these choices made (and I agree that Rosa going up against an Ancient Conspiracy would have made a far less personal game), but I wonder if some of those unanswered questions don't frame a different story.
Specifically: What happened to the Energy Vampires?
Theory: Taken out by Sam Durkin.
As far I recall, the game gives no explanation for why Durkin disappears just as the main case in Epiphany is going critical, and I think it's because he has even bigger fish to fry. He may not be a Bestower, but there's probably no one better in the city to take on this particular threat. After all, he was first on the scene when Lauren Blackwell started to Embrace Eternity- who knows what she might have babbled as all the information in the universe coursed through her? He almost certainly remembered her name from a mysterious phone call a few years ago, asking odd questions about his deceased mother, and we know he followed Rosa Blackwell's movements with some interest.
As a cop, he not only knew about the strange deaths in The Blackwell Deception, but he might have even searched the homes of Janet and Gavin, uncovering any number of ancient records and arcane secrets.
But real clincher for him would not have been the things he found, but the orders from above to turn a blind eye to them, to watch evidence being stolen away or destroyed outright. Orders from Commissioner Silva. Things come to head during Epiphany, when Rosa, the Bestower, is arrested, and Durkin has to either turn her over to Silva, or go completely rogue- taking Rosa onboard, drafting a trustworthy young cop as the ONLY policeman she can talk to, and then going after Silva himself. Maybe to just to protect Rosa at first or maybe he already knows that Silva is up to something even worse than murder. Clearly, there's only one real choice.
And after that, it's Gabriel Knight style race against time to uncover just what Da Silva and her strange cohort are up to. They have defenses against ghosts, Bestowers, and all things supernatural, but maybe they aren't prepared, at this critical moment, for one determined guy with a gun.