While the first two seasons of Arrow were an extremely grounded affair (gritty enough to feel right at home on the big screen with much of DC's feature output so far), it opened the door to a meta-reality when it served as a launching pad for the spin-off series, The Flash. Starring Grant Gustin in the title role as well as alter ego Barry Allen, from out of the gate the series embraced its comic book roots, delivering larger-than-life adventures filled with metahumans – most of whom, just like Barry, were transformed from ordinary humans into something quite extraordinary due to an exploding particle.
What follows is a guide to 34 villains that The Flash has gone up against over the course of the show's first two seasons.
Alchemy
Voiced by Tobin Bell, this character, nicknamed Dr. Alchemy by Cisco Ramon, is a multi-powered meta-human intent on preparing the world for.... something. To do so, he is tranforming people who were meta-humans in the Flashpoint timeline back to their enhanced selves. First appeared vocally in "Flashpoint" and physically in "Paradox" (season three).
Atom Smasher
AKA Albert Rothstein. Played by Adam Copeland, an Earth-2 character who is endowed with incredible strength and the ability to grow in size. Appeared in "The Man Who Saved Central City" (season two).
Blackout
AKA Farooq Gibran. Played by Michael Reventar, he has the power to harness and unleash electricity. Appeared in "Power Outage" (season one) and "Flash Back" (season two).
Black Siren
AKA Laurel Lance. Played by Katie Cassidy, she is the Earth-2 version of Black Canary, the character from Arrow. She, too, is equipped with a sonic scream. Appeared in "Invincible" (season two).
Bug-Eyed Bandit
AKA Brie Larvan. Played by Emily Kinney, she's a technical genius and killer who's a rival to Arrow's Felicity Smoak. She utilises robotic bees to deadly results. Appeared in "All Star Team Up" (season one).
Captain Cold
AKA Leonard Snart. Played by Wentworth Miller. Armed with stolen cryonic technology in the form of a gun that will freeze anything, he enjoys a crime spree until he comes up against The Flash. Eventually he ends up part of the Legends Of Tomorrow team. Appeared in "Going Rogue," "Revenge of the Rogues," "Rogue Time," "Rogue Air" and "Fast Enough" (all season one), as well as "Family of Rogues" and "Running To Stand Still" (both season two).
Clock King
AKA William Tockman. Played by Robert Knepper, it's a character who originally debuted on Arrow. Appeared in "Power Outage" (season one).
Deathbolt
AKA Jake Simmons. Played by Doug Jones, he has the ability to harness plasma energy. The character debuted on Arrow. Appeared in "Rogue Air" (season one).
Deathstorm
AKA Ronnie Raymond. Played by Robbie Amell, this is the Earth-2 version of Firestorm who has supplanted the Dr. Martin Stein portion of his consciousness. He's married to that world's Killer Frost (Caitlin Snow in 'our' world) and they both work for Zoom. Appeared in "Welcome To Earth-2" (season two).
Doctor Light
AKA Linda Park. Played by Malese Jow, on Earth-2 she's a small-time thief turned metahuman who can absorb and use power from starlight. She appeared in the episodes "The Darkness And The Light" and "Enter Zoom" (both season two).
Everyman
AKA Hannibal Bates. Played by Martin Novotny, his metahuman ability allows him to shapeshift to look like other people. Appeared in "Who Is Harrison Wells?" and "The Trap" (both season one).
Geomancer
AKA Adam Fells. Played by Adam Stafford, his metahuman ability is to create earthquakes. Appeared in "Welcome To Earth-2" and "Escape From Earth-2" (both season two).
Girder
AKA Tony Woodward. Played by Greg Finley, his meta ability is to turn his skin to steel. He was a childhood bully to Barry Allen, and is happy to continue the pattern. Appeared in "The Flash Is Born" and "Power Outage" (both season one) and "The Runaway Dinosaur" (season two).
Golden Glider
AKA Lisa Snart. Played by Peyton List, she is sister to Captain Cold himself, Leonard Snart. She utilises a gun that turns objects into gold. Appeared in "Revenge Of The Rogues," "Rogue Time" and "Rogue Air" (all season one), and "Family Reunion" (season two).
Griffin Grey
Played by Haig Sutherland, he has the power of super strength, with the unfortunate side effect that each time he uses it, he ages. Appeared in "Back To Normal" (season two).
Grodd
David Sobolov provides the voice to this CG-created telepathic, and highly-intelligent, gorilla who is the result of being experimented on by Eobard Thawne. Appeared in "Crazy For You," "Fallout" and "Grodd Lives" (all season one), and "Gorilla Warfare" (season two).
Heatwave
AKA Mick Rory. Played by Dominic Purcell, an arsonist who is frequently partnered with Leonard Snart, he utilises a heat gun that has the ability to burn pretty much anything. A regular on DC's Legends Of Tomorrow. Appeared in "Revenge Of The Rogues" and "Rogue Time" (both season one).
Killer Frost
Played by Danielle Panabaker, she is Caitlin Snow's doppelganger from Earth-2. She has the ability to freeze things and use ice as a weapon. Appeared in "Welcome To Earth-2," "Escape From Earth-2" and "Back To Normal" (all season two).
King Shark
AKA Shay Lamden. Voiced by David Hayter, this CG-created character is from Earth-2 and sent to this Earth by Zoom to destroy The Flash. Appeared in "The Fury Of Firestorm" and "King Shark" (both season two).
Magenta
AKA Frances Kane, she is played by Joey King and is a meta-human capable of creating magnetic energy from her mind. First appearance in "Magenta" (season three).
Mirror Master
AKA Sam Scudder. Portrayed by Grey Damon, he's a meta-human who can actually enter any reflective material and can use this power to trap others in that alternate dimension. First appearance in "The New Rogues" (season three).
Mist
AKA Kyle Nimbus. Played by Anthony Carrigan, he has the power to turn himself into a poisonous mist. Held in the S.T.A.R. Labs prison, he was eventually freed by Leonard Snart. Appeared in "Things You Can't Outrun," "Power Outage" and "Rogue Air" (all season one).
Multiplex
AKA Danton Black. Played by Michael Christopher Smith, he's a metahuman that has been endowed with the ability to make multiple copies of himself. Appeared in "Fastest Man Alive" (season one).
Peek-A-Boo
AKA Shawna Baez. Played by Britne Oldford, she's a metahuman who has the power to teleport. Appeared in "Crazy For You" and "Rogue Air" (both season one).
Pied Piper
AKA Hartley Rathaway. Played by Andy Mientus, he's a criminal armed with sonic gloves. After a trip through time, Barry inadvertently alters things to the point where Rathaway becomes an ally to Team Flash. Appeared in "The Sound And The Fury" and "Crazy For You" (both season one) and "Flash Back" (season two).
Plastique
AKA Bette Sans Souci. Played by Kelly Frye, she's a former war veteran with the ability of causing anything she touches to explode. Appeared in "Plastique" (season one).
Prism
AKA Roy Bivolo. Played by Paul Anthony, he's a metahuman who can induce uncontrollable rage in others. Appeared in "Flash Vs Arrow" and "Rogue Air" (both season one).
Reverb
Played by series regular Carlos Valdes, he is the doppelganger of series regular Cisco Ramon. Besides having flashes to the future as Cisco does, he can manipulate sonic vibrations to create powerful shock waves. Appeared in "Welcome To Earth-2" (season two).
Reverse-Flash
AKA Eobard Thawne pretending to be Harrison Wells. Thawne is played by Matt Letscher and Wells by series regular Tom Cavanagh. Thawne is a speedster from the future who is responsible for the death of Barry's mother and is in the present to manipulate Barry for his own purposes. Letscher appeared in "Tricksters" and "Fast Enough" (both season one), as well as "Potential Energy" and "The Reverse Flash Returns" (season two).
The Rival
AKA Edward Clariss and played by Todd Lasance. He's a villainous speedster of the Flashpoint timeline, and arch enemy of Kid Flash. In the main timeline Clariss is a human transformed back into a meta-human by Alchemy. First appearance in "Flaspoint" (season three).
Sand Demon
AKA Eddie Slick. Played by Hett Turton, he has the power to turn part of his body into sand, which can be manipulated in deadly ways. Appeared in "Flash Of Two Worlds" (season two).
Shade
Alter ego TBA. Played by Mike McLeod, he's a methuman who can vibrate his molecules to such a high frequency that he appears to be a looming — and deadly — shadow. First appearance in "Shade" (season three)
Tarpit
AKA Joey Montelone. Played by Marco Grazzini, he has the power to transform into molten asphalt. Appeared in "Fast Lane" (season two).
Top
AKA Rosa Dillon. Played by Ashley Rickards, her meta-human ability is to instill vertigo in her opponents. First appeared in "The New Rogues" (season three).
Trajectory
AKA Eliza Harmon. Played by Allison Paige, she is another speedster but with a split personality. Appeared in "Trajectory" (season two).
Trickster
AKA Axel Walker. Played by Devon Grae, he's a young copycat of James Jesse, the original Trickster who also happens to be his father (and played by Mark Hamill, who originally played the part in the 1990s Flash TV series). Both Grae and Hamill appeared in "Tricksters" (season one).
Turtle
AKA Russel Glosson. Played by Aaron Douglas, he can actually slow time. Appeared in "Potential Energy" (season two).
Vandal Savage
Played by Casper Crump, he's an immortal first introduced during a crossover with Arrow, and then featured as the primary antagonist of season one of DC's Legends Of Tomorrow. Appeared in "Legends Of Today" (season two).
Weather Wizard
AKA Mark Mardon. Played by Liam McIntyre. As his name suggests, he's been given the power to manipulate the weather around him, to deadly results. Appeared in "Out Of Time," "Rogue Time" and "Rogue Air" (all season one), as well as "Running To Stand Still" (season two).
Zoom
AKA Hunter Zolomon. Played by Teddy Sears, he initially pretends to be The Flash of Earth-2 but is eventually revealed to be the villainous speedster, Zoom, 'big bad' of the show's second season. Tony Todd provides the voice for the character when he's masked. Appeared in 19 of the 23 episodes in season two.