An Explanation of DC's Multiple Universal Reboots and How to Navigate DCU Canon
This is an expansion of a shorter explanation I gave on my Batfam Starter Recs reading list. I figured it might be helpful to have it as a standalone explanation for new comic readers learning how to navigate DC's various attempts to deal with the concept of canon.
The Multiverse is a storytelling device within DC Comics that explains how most of the comics DC has published are tied together or are separate from each other. There exists a "main" universe, where most of DC's published comics collectively take place, and then several alternate universes where things happened differently than they did in the main universe. The multiverse allows writers to explore various concepts like "what if the Jack the Ripper murders happened in Victorian-era Gotham?" and "what if DC's women were the primary heroes of their universe and fought in World War II?" without affecting anything going on in the main universe.
DC Comics canon works in three "mainline" universes:
the pre-Crisis universe (everything published from the beginning of DC Comics until the Crisis on Infinite Earths event in 1986)
the post-Crisis universe (everything published between 1986 and 2011)
the post-Flashpoint universe (everything published from 2011-now)
In the 1980s, management at DC decided that continuity had become too outdated, convoluted, and contradictory to tell coherent stories within a shared universe as more stories were told, new characters were introduced, and new context to prior stories was added. The company had previously attempted to solve this problem in the 1960s by publishing "Flash of Two Worlds," assigning existing stories to two different universes (Earth-One and Earth-Two), and creating a smattering of other alternate universes (Earth-Three was the home of the Crime Syndicate, evil AU versions of the Justice League, for example), but found that this did not actually solve the issue.
So. They decided to do a total universal reboot. That reboot was initiated by the company-wide crossover event known as Crisis on Infinite Earths, published from 1985 to 1986.
COIE effectively rebooted the entire internal DC Universe from the dawn of time onward. A new universal history now existed: the vast majority of characters/character history, history, and events from the varying alternate timelines that existed in the previous universe were retold, retooled, condensed, and/or thrown out in favor of a new, theoretically streamlined single reality. From 1986-2011, DC Comics mainline continuity was published in this shared universe, which industry professionals and fans alike called the 'post-Crisis' universe; in-universe, we refer to this primary version of DC's continuity "New Earth" (or occasionally, Earth-0).
For a wide variety of reasons that I won't get into here, DC completely rebooted their universe again in 2011 following the Flashpoint event comic. This new primary universe—interchangeably called the New 52 universe, post-Flashpoint universe, or Prime Earth, depending on the conversation—once again drastically changed many characters’ histories, personalities, and relationships with each other (sometimes for the better, most of the time for the worse). This is the current universe for DC's main comic line.
Within these three overarching iterations of the DCU, there were several events aimed to clean up, refresh, or reorganize various continuity problems. You may hear people refer to "post-Zero Hour" continuity, for example, to describe post-Crisis events/character histories that were revamped after Zero Hour: Crisis in Time! was published in 1994. "post-Rebirth" continuity, another common descriptor, refers to the reorganization of the post-Flashpoint/Prime Earth universe that happened after the Rebirth event in 2016.
GENERALLY SPEAKING, these are the most common ones you'll hear about:
Pre-Crisis Universe (1937-1986): "Flash of Two Worlds" (1961)
Post-Crisis Universe (1986-2011): pre/post-Zero Hour (1994-2005), post-Infinite Crisis and One Year Later (2005-2008), & post-Final Crisis (2008-2011)
Post-Flashpoint Universe (2011-present): The New 52 (comics written from 2011-2015), Convergence/DCYou (the first attempt to fix New 52 continuity, lasted from 2014-2016), pre/post-Rebirth (2016-2021)—and within Rebirth continuity there were two events, Dark Knights: Metal and its sequel, Death Metal, that did some minor universal revamps (2018-2021)—and post-Death Metal continuity, also known as Infinite Frontier (2021-present). Dark Crisis (2022) also exists but didn't really change the multiversal lore status quo, just simplified the explanation.
Other important universal lore-related things to note about these events:
Prior to Crisis on Infinite Earths, the DCU was an "infinite multiverse." There were no limits on the number of alternate universes that existed and no in-depth explanation for how they were connected or unconnected to the DCU's main timeline.
COIE destroyed the infinite multiverse and condensed everything into one, single universe. Between 1986 and 2005, there were technically no acknowledged alternate universes beyond the "antimatter universe."
"Hypertime" was created by Mark Waid and Alex Ross in 1999 as a way to get around this rule and eventually became the "go-to" way of explaining and fixing various continuity errors. Hypertime is a network of alternate timeline "echoes" that branch off from the main DCU timeline and occasionally overlap with each other, causing alterations in reality.
Since there could only be one timeline, continuity discrepencies were often "fixed" by explaining that one version of events happened in a previous, now destroyed timeline (that characters may or may not remember). Characters could cross from one timeline to another if needed, but any changes resulting from time travelers messing with events caused the destruction of their orginal timeline.
The "Elseworlds" imprint was another method of writing alternate universe stories without explicitly acknowledging the multiverse existed. DC officially just called these books "non-canon" stories without trying to explain how they existed in relation to the main universe. Most if not all of these stories are now considered part of the multiverse.
The infinite multiverse was briefly restored after Infinite Crisis in 2005 and then merged into a single 52-universe multiverse the year afterwards in 52. This new, limited multiverse was explained as there being an "original" Earth (Earth-0) with each successive universe being further and further removed from that one.
The initial post-Flashpoint/New 52 explanation of the multiverse was that there was a limited 52-universe multiverse. That explanation was somewhat overwritten after Rebirth and fully retconned after Death Metal.
Death Metal introduced the concept of the "omniverse," a multiverse of infinite multiverses. Yes, this is dumb. Yes, we generally ignore it and it has now been fully retconned.
The "Dark Multiverse" (a temporary "dark negative counterpart" of each Multiverse reality created by the fears of a universe's people) is theoretically a thing that exists. No, no one else really understands it either and the concept is generally restricted to the two Metal events.
Since Dark Crisis, the DCU is once again a single infinite multiverse in the vein of late pre-Crisis continuity. Every universe and continuity exists, and some are closer to the mainline reality than others.
Right now, the main DCU is once again a singular multiverse with an infinite number of universes. Technically, every version of "mainline universe" history throughout the existence of the multiverse is now considered to have occurred and is remembered by the inhabitants of Prime Earth. In practice, this means that "everything is nebulously canon or non-canon until explicitly acknowledged by a writer to have definitively happened and/or be something that a character remembers happening to them."
Unfortunately, not a lot of writers are doing much with that concept right now outside of picking and choosing their favorite parts of mainline canon to focus on and/or re-canonize, but it at least presents a path forward where a lot of the continuity and characterization issues created by the New 52 reboot are able to be properly addressed.
I hope this explanation was helpful for people, and I'm happy to try and field any further questions as well!
