Arrow recently added another major player to the Season 5 lineup with the debut of Adrian Chase (played by Josh Segarra), a character who will have increased importance on the show.

Who Is Vigilante?

The Oliver Queen Connection

Friend Turned Foe

Prometheus' Motivations

For now, Chase is simply Star City's new District Attorney, but it's only a matter of time until the show begins exploring his nightly exploits as the costumed hero Vigilante. As both DA and Vigilante, Chase looks to be a valuable ally in Oliver Queen's never-ending crusade to save his city. But is that really the case? We think that not only is Chase more foe than friend to Team Arrow, but he may even be the man underneath Prometheus' hood. Here's our theory about how the two characters are one and the same.There have been a number of DC heroes to use the Vigilante name, dating all the way back to the Wild West crusader of the 1940's. But Adrian Chase is probably the most well-known and psychologically complex version. He first debuted in an issue of Teen Titans in 1983 and eventually went on to star in his own solo series. Chase was cast as a sort of morally conflicted version of the Punisher. He preferred to use nonlethal force but often struggled to adhere to his moral code when faced with the evils of the world. As the series progressed, Chase became more and more psychologically unhinged. The series actually culminated with a guilt-ridden Chase committing suicide, which, needless to say, was a pretty bold move for DC.We doubt it's a coincidence that this is the version of Vigilante the Arrow writers chose to throw into the mix. Just as the comic book version of Adrian Chase was destroyed by his quest to defeat evil, we expect that Arrow's Chase will deal with plenty of psychological turmoil over the course of this season. Perhaps enough turmoil to cause him to serve as the Green Arrow's most important new ally and most dangerous new foe?At the moment, we know very little about Prometheus or what plans he has in store for Star City. The main tidbit that's been revealed so far is that Prometheus has a very personal connection to Oliver Queen's past, suggesting some sort of Slade Wilson-esque rivalry is about to bubble up to the surface. Is it just coincidence, then, that we learned that Ollie and Chase have a shared history last week in "A Matter of Trust"? Granted, Ollie doesn't seem to remember their previous meeting and stealing away Chase's girlfriend. It happened back in the days when he was still a freewheeling billionaire playboy. But Chase remembers. And though he specifically told Ollie, "I'm not one to hold a grudge," we get the distinct impression he was being ironic.There's a definite sense that Chase is nursing a grudge against his old rival and current political colleague. The question is whether Ollie stealing his girlfriend is the true source of that grudge, or if there's more to their shared history Ollie doesn't remember. Maybe Chase is somehow connected to Ollie's short-lived career as a member of the Russian Bratva organization. Sooner or later the show will have to establish a more direct link between this season's flashback storyline and the present day. Maybe Chase was the victim in some crime Ollie committed as a Bratva enforcer. Perhaps Chase was Bratva himself. It would explain how he acquired his fighting skills and account for the character's warped view on justice and general psychological troubles.Probably the biggest piece of evidence linking Vigilante and Prometheus is the fact that the Arrow-verse shows have a long history of turning close allies into major villains. Malcolm Merlyn was revealed as the Dark Archer on Season 1. Slade Wilson evolved into Deathstroke on Season 2. Even on The Flash, Harrison Wells and Hunter Zolomon turned out to be evil speedsters in disguise.Chase revealing himself as Prometheus would simply be in keeping with that tradition. We expect the early part of Season 5 to focus on building a bond between Green Arrow and Vigilante, only to twist the knife with the reveal that Adrian Chase is secretly Star City's most terrifying new villain.One interesting question to ponder is whether Chase himself is even fully aware that he's both Vigilante and Prometheus. Depending how heavily the writers lean on the character's mental problems, we could see him being cast as Arrow's answer to Two-Face. For one thing, both Chase and Harvey Dent were District Attorneys before they entered the superhero realm. Both have a devotion to justice and troubled psychological profiles that cause their eventual downfall. We could see Vigilante and Prometheus being two sides of the same coin. Vigilante represents Chase's better, more noble nature, while Prometheus is his darker side. And depending what state his mind is in on any given night, he might suit up as one or the other.The "Prometheus" name probably offers a clue as to what motivates this villain. In Greek mythology, Prometheus is a Titan who gave the gift of fire to mankind and was punished by the gods. Prometheus brought forth knowledge and enlightenment and made civilization possible. But while humanity benefited from that enlightenment, Prometheus himself was doomed to an eternity of torture. Maybe Chase sees himself as a modern-day Prometheus. He tried to bring justice to his city and suffered as a result. And now he's determined to punish Oliver Queen and everyone else who failed to appreciate what he tried to do. It would be very appropriate if Prometheus chose to reclaim his "fire" by literally burning Star City to ashes. After all, it's tradition for every major Arrow villain to cap off the season by trying to destroy the city. Why stop now?

Who do you think Prometheus is? Let us know your theories in the comments below.Jesse is a mild-mannered writer for IGN. Allow him to lend a machete to your intellectual thicket by following @jschedeen on Twitter , or Kicksplode on MyIGN