Arrow did have some epic villains in its roster that only appeared for a single episode. But these Arrow villains left a lasting impact on everyone.
Chimera – The Vigilante Killer
The man known as Chimera once just used to go by the name of Kevin Meltzer. When Oliver was just learning the ways of the Arrow, he saved Meltzer’s life. Meltzer became so obsessed with vigilantism that he began attacking them and collecting their masks into his ever-growing collection. Equipped with a powered exo-skeleton suit and armor. Chimera became a force to be reckoned with. He terrorized the city’s heroes, becoming a vigilante serial killer. He was no pushover in combat either, having had enough skills to hold his own against multiple members of Team Arrow. His habit of collecting masks and his battle acumen made for a good Arrow villain. It is a shame we did not see more of him after episode 11 of season 7.
Clock King – The Underappreciated Genius
Clock King sounds like a joke character writers and creators came up with on a stupid dare while drunk. But William Tockman is a force of nature. He is meticulous and calculative as heck. Nothing he ever does is without meaning. His brilliant mind works just like clockwork. This genius villain was diagnosed with a deadly illness that is secretly killing him. Tockman uses his smarts to commit robberies so that he could pay for his medical bills. Later it is revealed that the real reason Tockman is a criminal is to pay for his terminally ill sister, who is also dying. Tockman was a very intriguing character with a complex backstory that could have been fleshed out further.
The Dollmaker – The Creepiest Serial Killer Ever
Probably the scariest and creepiest Arrowverse villain, Dollmaker was basically a serial killer who targeted young women. His MO involved stalking and then kidnapping younger women and then killing them by turning them into macabre dolls. By himself, the Dollmaker is not much of a threat since he could easily be taken down. He has no real skill except being extremely creepy. It is his modus operandi that makes him an actual psychopath, even by the dark and gritty standards of Arrow. We would have liked if he was shown more in the future episodes of the show.
Mr. Blank – Coldest Gun For Hire
He looks like a hired gun. But he is much more than that. Mr. Blank is not like the other mercenaries shown in Arrow. He is cold, composed, and calm at all times. And he executes his mission with deadly precision and accuracy. Mr. Blank was one of the few hitmen who were able to sneak up on Oliver Queen, which is easier said than done. Blank was shockingly okay with killing a child in an elevator. He was more than happy to spill as much blood as he needs to so that he could get paid. That pushes the character into truly horror-slasher psychopath territory.
Garfield Lynns – The Man Who Played With Fire
The Firefly, in DC Comics, is a pyromaniac who burns first, asks questions later. In Arrow, the real name of Firefly is Garfield Lynns. Once a decorated firefighter, Lynns was left to die in a fire by his own team mates. He now returns to the city to exact revenge. Lynns is special because he was the first villain to teach Oliver a valuable lesson – not all bad guys are born evil. People like Lynns became criminals because society pushed them into a dark place. Lynns was just a good man pushed to the brink of insanity. When he dies via self-immolation at the end, we all felt his pain.