Warning: massive spoilers ahead for Episode 15 of Arrow Season 5, "Fighting Fire with Fire."
Arrow Season 5 has introduced its fair share of major mysteries, ranging from how Evelyn was turned from Team Arrow to why on Earth Oliver thought it was a good idea to date a reporter. The biggest mystery, however, has been the identity of the supervillain known as Prometheus. Arrow tried tease that Quentin could be the masked man, and it even went so far as to kinda sorta give him a name in the midseason finale, but it wasn't until "Fighting Fire with Fire" that we got a real answer, and it was one that few of us could have predicted. District Attorney Adrian Chase is Prometheus.
Of course, Arrow didn't go so far as to pull down Prometheus' mask, reveal Adrian Chase's face, and end on a declaration of "Yo, I'm definitely 100% the real Prometheus!" That said, it's not hard to connect the dots. The big fight sequence earlier in the episode was a giveaway, and for any who weren't convinced that what we were seeing was real and not another fake-out at that point, the final scene put the icing on the cake. Adrian stalked up to Susan as she walked alone to her car and creepily demanded to speak with her about "an exclusive." The not-entirely-subtle Prometheus theme blared over the scene as Chase's eyes bugged out, giving us our answer. The friendly D.A. is the not-so-friendly supervillain.
Arrow has pulled off some pretty epic plot twists in the past, but the reveal that Adrian Chase is Prometheus is definitely one of the craziest. Chase is a relatively well-known character in DC Comics lore, but he's definitely not a villain known for stalking the streets of Star City. The Adrian Case of DC Comics is a crime-fighter known as Vigilante, and fans everywhere have been waiting for the show to unmask Vigilante and get a move on with Chase's story as a superhero of sorts. The reveal that Chase is Prometheus was as big of a "Holy shit!" moment as I've ever gotten from Arrow. Not only was it a huge surprise; it also made a certain degree of sense, and that's really all I want from Arrow.
In hindsight, the reveal of Adrian Chase as Prometheus explains kind of a lot. For one thing, Chase has been surprisingly attached to and obliging of Oliver throughout Season 5. While it originally seemed that they were simply becoming pals because Arrow is Oliver's story and of course the new guy is going to start doing him favors, we now know that Chase had ulterior motives. He's not just a lawyer who doesn't ask too many questions about his boss; he's a bad guy with a plan of his own, and it's easy to see why Team Arrow hasn't captured him yet. He's ten steps ahead of them all. Hopefully the chase through the rest of the season will be filled with as many twists and turns as he's pulled off as Prometheus so far.
Judging by what we've seen of next week's episode, we won't have to wait much longer to see Oliver and Adrian Chase face off as open adversaries. The promo indicates that the good guys will face off against Prometheus in a bloody conflict that could end very badly for all of them, but especially the innocent Susan Williams. We'll have to wait and see.