Faora, being Zod's loyal second-in-command, is more like a different Kryptonian villain, Ursa—which is odd, because Faora and Ursa they were originally Decomposite Characters of the original comic book version of Faora. (Confusing, eh?)
Batman combines traits of his mainstream comic book, Batman: The Dark Knight Returns and Batman: Arkham Series incarnations. He also starts off like post-resurrection Jason Todd and Damian Wayne, willing to kill criminals before growing out of it. As revealed in Zack Snyder's Justice League, Batman also takes on the role of Adeline Kane in causing Deathstroke's missing eye. While Batman is sometimes a hero who goes up against Deathstroke, him being the one Deathstroke seeks revenge on is specifically taken from Dick Grayson, who Zack Snyder has confirmed died as Robin in this continuity.
Lex Luthor is actually named Alexander Luthor, Jr., a separate character from the comics who happens to be the son of an alternate Lex. He also starts off with a full head of hair like in Superman: Birthright before losing it and more closely resembling the classic Lex.
Doomsday is created from the corpse of General Zod. His creation, with Zod being infused with Luthor's blood, also invokes the origins of the Conner Kent Superboy and Nuclear Man and he also has energy absorption abilities like the Parasite.
While the film version of Deadshot still carries the comic incarnation's nihilism, the casting of Will Smith and Smith's own comments about Deadshot trying to rid the world of worse criminals suggests elements of the original Eric Needham Black Spider (an African-American vigilante who fought criminals) were infused into this version of Deadshot.
June Moone's role as Rick Flag's love interest on the Squad who he can't bring himself to kill after she betrays the team is taken from Dr. Karin Grace.
Dr. Sivana combines his own role in Geoff Johns's Shazam! origin with that of Black Adam (thinking he has the right to the Shazam powers and demands Billy transfer them to him) and Byers/Sabbac (empowered by the Seven Deadly Enemies of Man; the Byers brothers appear in the film, but their father doesn't).
Thanks to budgetary restrictions, Birds of Prey (2020) combined Bud and Lou, Harley Quinn's pet hyenas from the comics, into a single hyena named Bruce (named for Bruce Wayne as a joke).note The only options for depicting them were two CGI hyenas played by men, or one played by a dog, the latter was chosen, which gave a more justified case of the All Animals Are Dogs behaviors that the hyenas showed originally.
Cyclone takes Stargirl's (who was originally intended to be in the film before being removed in subsequent script revisions) role as Atom Smasher's potential love interest.
The Justice Society being depicted as working for Amanda Waller and ARGUS is based on ARGUS' Justice League of America from the New 52, the organization's counterpart to the regular Justice League.
The Michael Keaton version of Bruce Wayne from Batman (1989) takes Flashpoint Thomas Wayne's role as the older, alternate timeline Batman who teams up with Barry.
Supergirl takes the Flashpoint version of her cousin Superman's role as the sun-starved Kryptonian survivor who was imprisoned by the military after landing on Earth. Also, while she's the Kara Zor-El incarnation of the character, her costume and black hair more closely resemble those of the Lara Lane-Kent version of Supergirl from the Injustice comic books.
Dark Flash is named for an alternate version of Wally West, his black costume resembles the Black Flash, the grim reaper of the speedsters, as well as the Daniel West version of Reverse-Flash, Barry Allen's Evil Counterpart from the New 52Flash run. And his true identity as a corrupted alternate version of Barry is similar to the Future Flash, also from the New 52 era.
Victoria Kord's role as an antagonistic family member of the previous Blue Beetle, Ted Kord, is taken from his uncle Jarvis Kord, while her role in creating the OMAC program is derived from that of Maxwell Lord, whose only connections to Ted Kord in the comics were working with him as part of the Justice League International and murdering him (whereas the DCEU's Ted has instead mysteriously vanished).
Ignacio Carapax is named for Carapax the Indestructible Man, the archenemy of Ted Kord, but takes on the identity of OMAC, similar to Buddy Blank, the original OMAC.
Live-Action TV
Peacemaker (2022): Christopher's Right Wing Militia Nut father Auggie Smith is also the armored supervillain White Dragon, an identity that instead belonged to the white supremacist vigilante William Heller in the Suicide Squad comics.
