Given that there are thousands of comics set in it and hundreds of writers working on it, The DCU is prone to continuity inconsistencies.
- Ed Brubaker's run on Catwoman reintroduced Holly Robinson, Selina's room-mate and sex-work protegee from Batman: Year One and Her Sister's Keeper, as her new sidekick. Unfortunately, Holly had previously been killed off, after being given completely different Character Development as a mob wife, in a story from the Action Comics Weekly anthology series. Rather than make any attempt at Retcon, Brubaker simply acknowledged the error in a short Leaning on the Fourth Wall comedy piece included in the Catwoman: Secret Files and Origins one-shot. He admitted both in the piece and in interviews that he simply hadn't known about Holly's death, given the relative obscurity of the comic where it happened. The intervening Zero Hour: Crisis in Time! Cosmic Retcon provides an easy in-universe explanation for fans who really want one.
- Convergence: There are a number of these scattered throughout the tie-in issues, mostly fairly minor, but they do stand out to those familiar with the time period in question.
- Captain Marvel is referred to as "Shazam" several times, despite the fact that his name was not changed to Shazam until the New 52.
- Both Pre-Crisis Barry Allen and Jay Garrick refer to the Speed Force, something neither of them should have any knowledge of since the concept wasn't created until the post-Crisis Wally West Flash series. Barry's opponent, Tangent Comics Superman, mentions this.
- 90s hook-handed Aquaman is pining for Mera, but the two of them were separated and not on good terms at all during that time period.
- Kyle Rayner's ring talks to him and welcomes him back to the Green Lantern Corps, but the Corps was disbanded when he first became a GLnote , and Kyle's ring rarely spoke to him, if ever. He shouldn't know anything about Qward either, having not encountered the Weaponers that early in his career.
- Kyle views Hal and Parallax as two separate entities. This is consistent with the Geoff Johns' Green Lantern: Rebirth retcon that made Parallax a fear entity that possessed Hal, but before the retcon, Hal was Parallax. Note that the fear entity never appears or is referenced, and Hal's sanity while depowered is consistent with the post-Zero Hour zero issue of Green Lantern, so this may not be a continuity error so much as an attempt to remain mostly consistent with the past while keeping the retcon in mind.
- The summary of the events of Emerald Twilight is wrong. Hal didn't kill all the other Green Lanterns. He defeated them and took their rings, but he left them enough power to survive. And indeed, most of them turn up later on during Geoff John's run and are collectively known as the Lost Lanterns. Similarly, Hal didn't kill the Guardians either. They pooled their power and put everything they had into Ganthet, who created a ring for Kyle. Hal absorbed all the power of the central power battery into himself.
- In "Batman and the Outsiders", Commissioner Gordon has red hair. He should have white hair and a white moustache in any pre-Flashpoint appearance, with the exception of stories like Year One that are set in the past.
- Supergirl is wearing the wrong costume for her death scenes from Crisis on Infinite Earths. Also, her father Zor-El didn't work on the Phantom Zone projector.
- Matrix is called Kara several times, even though that was never her name since not being Kara Zor-El was her raison d'etre.
- Though the inconsistency could be excused somewhat by the story aiming for a more humorous and irreverent tone, the Supergirl: Matrix tie-in establishes Lord Volt and Lady Quark to resent each other with the heavy implication that it's because they're gay and have been forced into an Arranged Marriage. This is in disregard of Crisis on Infinite Earths establishing Lady Quark as genuinely loving her husband and being upset about his death after she becomes the sole survivor of her world when it was wiped out from existence by the Anti-Monitor.
- The Crime Syndicate tie-in miniseries uses the Pre-Crisis Crime Syndicate, but mistakenly uses elements from later incarnations of the Crime Syndicate. Superwoman is referred to as Lois Lane by several of her fellow Crime Syndicate members and Owlman is referred to as Thomas, when Pre-Crisis Earth-3 Lois Lane was a separate character from Superwoman and the wife of that reality's Lex Luthor and Pre-Crisis Owlman never had his real name revealed, with the Superwoman and Owlman of the Antimatter Crime Syndicate that was introduced in JLA: Earth-2 respectively having Lois Lane and Thomas Wayne, Jr. as their civilian names. In addition, Johnny Quick mocks Owlman for never having any powers (when Pre-Crisis Owlman had the power of mind control with the later versions of Owlman being Badass Normals like Batman) and the story features heroic counterparts to the Flash's Rogues called the Rogue Hunters as well as mentioning the death of a benevolent counterpart to Bruno "Ugly" Mannheim, which contradicts that the Pre-Crisis Earth-3 was established to have the Crime Syndicate as that world's only existing super-powered beings and its version of Lex Luthor was the only heroic counterpart to a villain from the standard DC Universe who was confirmed to exist.
- Pre-Crisis Captain Atom is referred to as Nathaniel Adam — the name of the Post Crisis Captain Atom — rather than Allen Adam.
- Parallax focuses his power through a ring when he kills Deimos. Parallax has internalized the power of the Main Power Battery and doesn't use a ring. The tie-in issues depict this correctly, it's just the main series that gets it wrong.
- The Legion Of Superheroes that battles Earth-4's Charlton heroes seems to be some weird mix of the post-Zero Hour Legion and the pre-Zero Hour temporal duplicates of the original Legion that wore very similar costumes (Batch SW6, who starred in Legionnaires). It includes the characters from Legionnaires who weren't duplicates of existing characters like Computo and Catspaw, neither of whom appeared in the reboot, but it also includes Timber Wolf and Princess Projectra, neither of whom were in Legionnaires (their SW6 selves were killed during the Dominator war) and both of whom look like their reboot selves (particularly obvious in Jeckie's case, since it means she's a giant snake). Characters who were dead/radically altered by the end of the reboot aren't, and everyone with different costumes in the two versions is wearing the SW6 version. Except Element Lad, who's wearing his pre-Zero Hour adult self's costume.
- The status quo of the West family is that of the final issues of Wally's own series. This changed dramatically in Flash: Rebirth. The idea that pre-Flashpoint Gotham was taken before Barry's return (i.e. three years before Flashpoint) doesn't jibe with any of the other stories.
- The beginning of Issue 6 is baffling when it comes to the continuity of the main DCU. You have the Justice League talking to the Justice League United (which formed after Forever Evil (2013)). Okay. Telos, the planet, is being transported into the universe, which has drawn attention of several parties. You have the Oracle being from the Superman books, Nix Uotan from The Multiversity, and Darkseid taking notice. That's all fine. But you have Jediah Caul and K'rot from the short-lived Threshold booknote , the Red Lanternsnote , and the freaking Guardians of the Universenote . And Blue Beetle is there too, still stuck in space apparently. It also might have a continuity hiccup with itself, as the Barry Allen that Earth 2 Jay Garrick meets implies he was grabbed after meeting Psycho-Pirate from Crisis On Infinite Earths, which flies in the face of the Barry Allen from his own tie-in, who was taken when he first left the future to say hi to his friends, before he was set on his death course, and was stuck under a dome for a year.
- Legion Of Superheroes: Legion of 3 Worlds mostly does a good job in keeping track of the different Legions. However, the flashback to their Forgotten First Meeting is meant to show the Legions as they were in their respective early days, and while it gets most of them right, it shows Reboot Brainiac 5 looking the same as he does in the "present"; short hair, Brainiac-logo forehead disks, and a costume with black sides and a purple front. In the early post-Zero Hour years he had shoulder lenghth hair, no disks, and his costume colours were reversed. And the scene also shows Kid Quantum I and Leviathan, who both died before Brainy got his cosmic makeover in LSH #104.
- Wonder Girl: Donna Troy's entire existence resulted from such an error. Teen Titans originated as a team-up of several sidekicks. But it was completely forgotten by the writers that Wonder Girl wasn't Wonder Woman's sidekick, she was Wonder Woman herself as a teenager. When somebody remembered this fact, the retcon to explain it gave the Titans' version of Wonder Girl her own identity as Donna Troy and (eventually) a truly convoluted history.
- Superman:
- In Superman (Brian Michael Bendis), Daily Planet reporter Robinson Goode used to work for the Star City Sentinel. Problem - in the post-Flashpoint DCU, there is no Star City; it was briefly used as a new name for Seattle in the Green Arrow (Rebirth) storyline "Rise of Star City", but then it reverted back to being Seattle.
- The Hunt for Reactron has Supergirl and her friend Thara to go camping on Krypton, and shows Kara enjoys tinkering with machines. Still, in Superman/Supergirl: Maelstrom, published only two years earlier, Kara is constantly complaining that she is a city girl who is not used to spend time outdoors, and at one point she states she is not a mechanic.
- In "Superman vs. Muhammad Ali", Superman does not know a thing about boxing, contradicting Adventure Comics #273 wherein Clark Kent learned to box.
- In "Krypton No More", an orange sun halves Kryptonians' powers and causes them blindness, contradicting previous story "The Unknown Legionnaire" where Superboy states an orange sun has no effect on him at all.
- In Supergirl Special Kara barely remembers her life back in Krypton, contradicting one of her more firmly established character traits which was constantly remarked upon in the Superman comics published in 2023. She also resents Power Girl's existence, even though the Power Girl Special published four months before revealed that she regards her alternate self as beyond family, and she does not understand why PG considers her "rival".
- In Superboy (1994) #89, a tie in to Our Worlds at War, Superboy is looking after a young clone of the Guardian, who says he remembers being a soldier and is scared he'll have to be one again. It's not clear where the clone gets these memories from, but it's not the original Guardian; Jim Harper was a policeman and therefore did all his fighting, both in constume and out, on the home front, with a previous story having specifically played on his guilt that he never saw action in WWII.
- Tales from the Dark Multiverse:
- In the version of Blackest Night, it's stated that the reason things ended in the original story like they did is because Sinestro shared the White Lantern power — except that's not what happened. What happened in the original story was Nekron ripped the Entity from him and it was Hal who took it and shared it. Likewise, it treats the Black Lantern infection like a typical zombie plague and the members of the Black Lantern Corps as the actual person reanimated when in reality one usually becomes a Black Lantern with an existing member ripping out that person's heart and they're actually a soulless corpse posing as the original, not that person themself reanimated.
- The version of events in the Dark Nights: Metal one-shot shows what'd happen if this went wrong — only the premise is the normal DC multiverse meeting the Dark Multiverse for the first time — but it's all the Dark Multiverse in the one-shot. That said, the ending of Metal's sequel Dark Nights: Death Metal turned the DC Multiverse into an Omniverse, so it's possible to reconcile that problem now.
- The version of Crisis on Infinite Earths (actually based more on Last Days of the Justice Society) has Surtur claim he already killed a Wonder Woman. But whether New Earth was primarily based on Earth-1 or Earth-2, there should still only be one instance of every character whose counterpart was an exact duplicate, including Diana.
- Earth 2: The third and final volume Earth 2: Society has a few glaring discrepancies in continuity in regards to the first two volumes, the most notable ones being that the god that gave Jay Garrick his powers as the Flash is misidentified as Apollo rather than Mercury as well as Alan Scott's ring stated to be an Oan power ring that chose him to be the Green Lantern and Sinestro being mentioned as one of the supervillains who menaced Earth during the Age of Wonders, which contradicts the earlier volumes establishing that Alan Scott's ring was the engagement ring of his deceased boyfriend Sam Zhao and was chosen because an object was needed to focus the power of the Green, in addition to the previous volumes giving no indication that the Green Lantern Corps existed in this continuity.
