Oliver Queen and his various allies have encountered many nefarious villains across the first seven seasons of Arrow, but none have the sheer saying power as Malcolm Merlyn. Loosely based off of the longtime Green Arrow villain Merlyn, who occasionally goes by the moniker the Dark Archer, the Arrowverse character has been present since the very first season of Arrow as its principal antagonist.

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Merlyn's presence would be felt for years to come across the Arrowverse, as a recurring villain on both Arrow and Legends of Tomorrow, with guest appearances on The Flash and Supergirl as well. And though Merlyn continued to grow as a powerful figure within the world's criminal underworld, he eventually underwent an unexpected heroic turn, shocking his former rivals and enemies. As Arrow prepares to wrap its penultimate season, here's a look back on one of the series' most complex characters.

Malcolm Merlyn And The Undertaking Of Arrow

Oliver vs. Malcolm Merlyn

Introduced as a high-profile businessman and partner with Oliver Queen's father Robert, Malcolm left Starling City after his wife's murder to train with the League of Assassins to avenge her death. Upon his return, Malcom begins secretly plotting to destroy the Glades neighborhood of the city, where his wife was killed. After learning of his business partner's plan, Robert declines in helping him, which results in Malcolm bombing his yacht, killing Robert and stranding Oliver on a remote island for five years.

Upon his return to Starling City as the vigilante, The Arrow, Oliver attempts to stop Malcolm only to discover that not only is the villain well-trained himself, but he also created a contingency plan which ensured that the Glades' destruction led to the death of Malcolm's son Tommy. Malcolm fakes his death as his role in the Undertaking (the name for the attack on the Glades) becomes public, only to return during Season 2 with the knowledge that he is the actual biological father of Oliver's sister Thea. Upon Thea's discovery of her parentage, she agrees to train under Malcolm, only for her father to hypnotize her and using her to kill the original Black Canary Sara Lance.

Malcolm Merlyn And The League of Assassins

Malcolm Merlyn aka the Dark Archer in Arrow

While continuing to train Thea and remaining on the run from the League of Assassins for a past betrayal, Malcolm learns that Ra's al Ghul has led his syndicate in a plan to unleash a deadly virus on Star City. Realizing he is not strong enough to face Ra's on his own, Oliver turns to Malcolm to similarly train him to be better prepared for a confrontation with the Demon's Head. Despite this, Thea is still mortally wounded in a battle against Ra's, prompting Oliver to save her life by immersing her in a mystical Lazarus Pit, a magical pool that completely heals users at the expense of making them more violent and psychotic. Malcolm grows infuriated that Oliver would go to those lengths to rescue his daughter at the cost of her soul.

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After killing Ra's in a duel, Oliver turns control of the League of Assassins and the title of the new Ra's al Ghul to Malcolm, intending to avoid leading such a murderous organization, with Ra's daughter Nyssa al Ghul pledging her loyalty to him. This proved temporary, as Nyssa would ultimately betray Malcolm by helping Team Arrow resurrect Sara with a Lazarus Pit before destroying it. After having Nyssa imprisoned, Malcolm creates his own inner circle of loyalists he refers to as the Thanatos Guild and tasks them with finding new Lazarus Pits around the world. Realizing the threat Malcolm and his supports present, Oliver has the Dark Archer fight Nyssa in a duel for control of the League before intervening and cutting off Malcolm's hand. Defeated, Malcolm then observes Nyssa officially disbanding the League of Assassins before going off to join Eobard Thawne, Damien Darhk and Leonard Snart in the Legion of Doom.

Malcolm Merlyn The Unlikely Arrowverse Ally

MALCOLM MERLYN Arrow

After disclosing the location of Oliver's long-lost son William Clayton to Damien Darhk, Malcolm is forced to turn to Oliver for help when Prometheus' men similarly kidnap Thea during Season 5. After Prometheus also kidnaps William, Oliver is forced to accept Merlyn's offer to join forces and break the new villain out of A.R.G.U.S. custody in exchange for their children's freedom. With Adrian Chase now on the loose as Prometheus again, a desperate Oliver and Malcom recruit Digger Harkness, Slade Wilson and Nyssa to help them in their fight, despite Merlyn's misgivings about teaming up with the woman who disbanded the League of Assassins after the loss of his hand.

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The ensemble make it to a remote island where Prometheus is allied with Nyssa's estranged older sister Talia. They are ultimately betrayed by Digger, who reveals himself as a mole within the group working for the two villains. After Thea accidentally steps on an old landmine, Malcolm forcibly takes her place rather than lose his daughter once again. As Digger leads a detachment of Talia's henchmen to confront Malcolm, the Dark Archer surprises the assembled killers by triggering the mine, killing himself and all the villains present including Digger as Thea watches from a distance.

A noble villain who values family and his legacy above all else, Malcolm Merlyn is one of the most entertaining villains to appear in the entire Arrowverse. While he has been dead since Season 5, DCTV's tendency to employ flashbacks, alternate worlds and hallucinations suggest that fans may not have seen the last of the longtime antagonist.

Airing Mondays at 8 p.m. ET/PT on The CW, Arrow stars Stephen Amell as Oliver Queen, David Ramsey as John Diggle, Emily Bett Rickards as Felicity Smoak, Rick Gonzalez as Wild Dog, Juliana Harkavy as Black Canary, Colton Haynes as Arsenal, Kirk Acevedo as Diaz and Katie Cassidy as Black Siren.