Characters from the DC comics

Below is a list of characters who originally appear in the DC comics multiverse prior to the episode's airing, by appearance.

Arrow
Characters first appearing in Arrow:

Comic book tie-in characters

 * 1) Khem-Adam
 * 2) Ravan Nassar ("Haunted") *
 * 3) Lyle Bolton

Upcoming characters

 * Liza Warner (unknown episode)

Notes:
 * 1) Thea is based on the comic book character, Mia Dearden, the second person to take on the mantle of Green Arrow's sidekick, Speedy, and the first to be a female.
 * 2) Even though Laurel is the actual version of Black Canary in Arrow, Sara Lance/The Canary, who is an original character specifically created for the show, is also based in part on the same character.
 * 3) Even though Malcolm is the actual version of Merlyn in Arrow, Tommy Merlyn, who is in part an original character specifically created for the show, is also based on the same character.
 * 4) Even though the character originates from the comics, his real name remained unknown. Unlike the comics, on the show he is given a real name, Winnick Norton.
 * 5) In the comics, Isabel is also known as The Queen. Ravager, which is the name she is informally given on the show, is the alter ego of several comic book characters, most of them related to Slade Wilson. The latest to don the moniker of Ravager is Slade's daughter, Rose Wilson, whose costume was the inspiration for Isabel's costume on the show.
 * 6) Sebastian's parents are both based on comic book characters as well. Sebastian Sangre is based in part on Sebastian Blood VIII who is the father of Sebastian Blood IX. Sangre means blood in Spanish. Maya Resik is based in part on Mother Mayhem. Both women who adopted the title, Anna Resik and May Bennett, were mothers of different Sebastian Bloods.
 * 7) Sin's real first name on the show has been revealed to be Cindy with her last name being still unknown. In the comics, her name is Cynthia and she got the surname "Lance" after she got adopted by Black Canary.
 * 8) Steelgrave is seemingly based on a minor Green Arrow foe, Professor Steelgraves (first name unknown), who is also mainly a weapon smuggler (though in the comics Steelgraves mostly fenced stolen high-tech devices).
 * 9) Even though Werner is the actual version of Count Vertigo in Arrow, the unnamed predecessor known as The Count, who first appeared in , is also based in part on the same character.
 * 10) Even though his first name was changed to "Curtis" for the show, he is based on the comic book superhero Michael Holt, the second Mr. Terrific.
 * 11) Even though the character originates from the mainstream DC comics, his last name was never revealed, as he was only known by his first name. Unlike the comics, in Arrow: Season 2.5 he is given a last name as well, Nassar.
 * 12) Even though in the comics his first name is unknown, he is based on a character known as Master Jansen who first appeared in Flash #218.

The Flash
Characters first appearing in The Flash:

Comic book tie-in characters

 * 1) Nathan Bliss/Mr. Bliss
 * 2) Shay Lamden/King Shark *

Upcoming characters

 * Doctor Light
 * Wally West (unknown episode)
 * Jesse Quick (unknown episode)

Notes:
 * 1) Even though Eobard is the actual version of Reverse-Flash in The Flash, Eddie Thawne, who is in part an original character specifically created for the show, is considered to be partly based on the same character, due to the similarity of their names.
 * 2) Even though the character originates from the comics, his last name was never revealed, as he was only known by his first name or his alias. Unlike the comics, on the show he is given a last name as well, Gibran.
 * 3) In the comics, Baez's first name is actually Lashawn but it was changed to Shawna for the show.
 * 4) Brie is a reimagining of the villain known as the Bug-Eyed Bandit, who in the comics is a male and is named Bertram Larvan.
 * 5) Al Rothstein is also the name of the Earth-1 equivalent of the character. This is in addition to a previous unrelated character with the same name, who was mentioned in.
 * 6) In the mainstream DC comics, King Shark's real name is an anthropomorphic Great White shark named Nanaue. The name Shay Lamden originates from The Flash: Season Zero.

Constantine
Characters first appearing in Constantine:

Referenced characters

 * 1) First of the Fallen
 * 2) Cedella
 * 3) Judith *

Notes:
 * 1) In the comics, Nommo is also known as Doctor Mist. In the New 52, his real name is established as Nommo Balewa.
 * 2) In the comics Judith is a minor character and a member of the Newcastle Crew. She has made only a few small appearances and most of the time she is just mentioned by other characters. Her last name is unknown.

Vixen
Characters first appearing in Vixen:
 * 1) Mari McCabe/Vixen

Referenced characters

 * 1) Anansi

DC's Legends of Tomorrow
Characters first appearing in DC's Legends of Tomorrow:

Upcoming characters

 * Rip Hunter ("Pilot, Part 1")
 * Vandal Savage (unknown episode)
 * Carter Hall/Hawkman (unknown episode)
 * Valentina Vostok (unknown episode)
 * Connor Hawke (unknown episode)