I'm going to pull this strait out of my ass, but there was a character that only appeared in one episode this season (Played by the same actor that did Nuke in Jessica Jones).....Remember the guy that stood in for Oliver when he was facing possible assassination, and ended up getting faux-killed in Oliver's place? ....a couple interesting things about that guy.... 1) He can face-change, so he could appear as literally anybody (presumably including the hot reporter chick) ...2) He appeared in BOTH the current-day setting AND the flashback setting with the Russian Mafia war.
I'm thinking that Prometheus *might* be retribution for something from Oliver's days in Russia and his Vendetta with the mafia boss rather than anything that happened since he's been the Arrow. Son of that one boss maybe? Would either leave plenty of room for the Reporter chick with the russian vodka to have a tie-in, OR opens the possibility that the real reporter is dead and has been replaced by the face-changer guy who now keeps his favorite russian brand stocked.
One flaw in my theory is we saw that guy help Oliver in both instances...(if I'm recalling the scene in Russia correctly... The time in Russia, I don't think Oliver ever saw him or knew anything about him.)
It is possible that guy was just a one-episode throw-away, but I really hope not....especially after having appeared in the flashback as well.
...it *would* explain how Prometheus seems to be so mega-plugged-in to everything that the police ever had on The Arrow.....from crime scenes to making those throwing stars out of Arrows that had been locked up in Evidence..... if Prometheus can face-change, there wouldn't be a need for a corrupt cop or some anti-Arrow guy on the police force.....he could just face-change into anybody who had legitimate access and take whatever he wanted at leisure.
