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Canon

No other fiction genre comes close to comic books when it comes to the concept of canon. The first reason is that most comic books, a 70 year genre, come on a monthly basis and can continue indefinitely. This raises many temporal problems in canon: Is Lois Lane actually over seventy years old? Did Captain America really fight Nazis during World War Two?

And over time, a character can go through different changes and have different writers. As anyone who has followed a character for a length of time would know, this poses problems, especially since quality or vision of the character may vary, and sometimes the plots can become so bad or so outrageous, people sometimes ignore a story in regards to canon. It could just be a technical issue like a character before could lift only 500 pounds, but in the latest issue, they're lifting something heavier than that. Was it an oversight? Will it be revealed later why that character has more strength?

Also, in comic books, there is some consistency and coherency expected within that comic universe. This is a problem in comics: take Batman for instance, he stars in multiple ongoing and limited titles, and can guest star in various other titles. All these have different writers with different ideas. Batman is also problematic because he's been in superhero titles like JLA, yet stars in more mundane detective stories. Also, as with Wolverine, people ask "how does he find the time to star in all his titles and do all those guest shots?" Some aspects of "reality" are ignored when it comes to canon, especially time aspects.

Another relatively unique feature of comics is that they re-re-re...tell origin stories. In each retelling, they can add or take away details which can contradict previous tellings. They can even give a fresh new origin without mention of the previous origin stories, and the reader has to infer that the latest origin story is the "correct" one.

A problem also lies, within the concept of canon itself, that is people have to agree what is canon, and there can always be differing opinions on what is canon or not.

Reboot

A reboot is a retelling or new envisioning of a story. It is similar to a remake (the term used for movies). A franchise's continuity begins anew, and/or elements of the continuity may be significantly retconned to accommodate a continuation of the series enabling writers to redefine characters and open up new story opportunities, and allowing the title to bring in new readers.

Star Wars Canon

In Star Wars canon, there are five different classes. If a higher class of canon contradicts something in a lower class, the events of the lower class are nullified. An example of this happening would be that in the novelization of The Empire Strikes Back, Hobbie Klivian dies when he crashes into an AT-AT. Because this didn't happen in the film, Hobbie was available to be used in later fiction such as Luke Skywalker and the Shadows of Mindor. The canon types are:

• G-Canon. This is the canon class for the films and is named for George Lucas. An example would be: Star Wars Episode IV: A New Hope.
• T-Canon. This is for television shows. An example would be: Star Wars: The Clone Wars.
• C-Canon. This is the canon for the Expanded Universe, it is for the comics, novels, video games etc. Star Wars: Dark Empire is an example.
• S-Canon. Any thing Star Wars that has not been officially confirmed whether it is canon or not falls under S-Canon. Some Star Wars: Tales comics are examples of this.
• N-Canon. N-Canon is confirmed as not canonical. Star Wars: Infinities - A New Hope is an example of this.

Star Trek Canon

Star Trek provides examples of two extremes regarding canon and comic books.

Original Star Trek

The creators of Star Trek defined the Star Trek canon as limited to the contents of television episodes and feature films. Star Trek comics, novels and other fiction are all non-canon in relation to the screen versions.

Alternate Universe

The alternate Star Trek universe that began with the 2009 film Star Trek presents the opposite case. Film writer Roberto Orci has consulted with the team creating the IDW Star Trek comics from the outset of this universe. The mini-series Countdown provided backstory for Nero, the villain of the 2009 film.

Similarly, the min-series Countdown to Darkness provided elements that appeared in the 2013 film Star Trek: Into Darkness. The plot of Section 31 that was introduced in this film continues to be developed in the on-going Star Trek comics. So the alternate Star Trek universe provides a rare example where films and comics create a single, coordinated canon.

Retcon

The term "Retroactive Continuity" or "Retcon" for short is used in comic books to define a re-write of a current origin or introduction of new information as if it had always been that way.

Definition

Retcon or retroactive continuity is a term that is used when writers reveal something new to a previous story already told which usually changes the original back story to something new. The term "Retroactive Continuity" was made known by All-Star Squadron writer Roy Thomas in the 1980s. Damian Cugley shortened the word to "Retcon" when Alan Moore re-wrote the origins of Swamp Thing in 1988.

At its simplest it can be a piece of information that alters a characters background, shedding some light on their reasoning and at worst a contradiction of a fundamental aspect or plot point of a characters previous established story arcs. The nature of comics to be the amalgam of many artists, writers and even publishers has the obvious flaw of over time their story becoming convoluted and errors and omission are bound to occur and means that ret-con can be as much of a plot device as it can be tool to correct previous errors.

List of Retcons

DC Universe related retcons

• In Crisis on Infinite Earths, after all the alternate Earths were destroyed, many heroes including Superman and Wonder Woman had their entire origins retconned and thus their series rebooted.
• In Infinite Crisis: Secret Files, there were several retcons that had an on-panel source. When Superboy Prime punched the barrier of reality he caused changes throughout the DC Universe including the resurrection of Jason Todd and the reboot of the Doom Patrol.

Batman related retcons

• The original killer of Thomas and Martha Wayne, Joe Chill was captured, however DC retconned it so the killer was never actually captured.
• Barbara Gordon was retconned to be Commissioner James Gordon's niece in Batman: Year One. Originally she was Jim's blood-related daughter.
• Bette Kane, the original Golden Age Batgirl, was retconned out of DC continuity to become Flamebird, a daredevil acrobat member of the Teen Titans West.

Daredevil related retcons

• When Frank Miller took over the run for Daredevil, he retconned Daredevil's history so that Stick, an Asian man, helped him develop and master his new abilities.

Marvel Universe related retcons

• In Tales of Suspense #64, Black Widow was told that if she stopped working for Russia, her parents would be killed. Years later, it was retconned that her parents had apparently died in a house fire when she was very young.
• At the end of his first appearance, Wonder Man died, but it was later retconned that he had had his brain patterns recorded just before dying (to help create the Vision), and then later retconned again that Wonder Man hadn't died, but gone into a sort of hibernation state whilst his body evolved from the ionic rays he'd been exposed to (despite that Vision had visited Wonder Man's grave in Avengers #66).

Spider-Man related retcons

• During the Clone Saga, Mary Jane had a baby and Aunt May died at the end of the story arc. When J. Michael Straczynski took over Spider-Man in 2001, he retconned it so those two events "never happened."
• Gwen Stacy's past was retconned when J. Michael Straczynski wrote the Sins Past story arc. This revealed that Gwen Stacy had an affair with Norman Osborn when she was in Europe mourning the death of her father.
• During One More Day, it was made that Spider-Man's marriage to Mary Jane never happened. And he lost his Other powers.

X-Men related retcons

• The Phoenix Saga was originally created by Chris Claremont for the Phoenix to actually be Jean Grey at the peak of her potential. Years after Jean's death, Marvel wanted to bring Jean back. However, bringing her back at first would bring many complications. If Jean were to be brought back, she would still be guilty for killing millions of life forms. Marvel announced that they would not bring back Jean unless someone creates a suitable resurrection story. Kurt Busiek (then a college student) and a few friends started pitching ideas. Eventually he would retcon Phoenix into a cosmic entity, and while Jean was piloting the shuttle, the Phoenix approached her and made an exact duplicate to use. While also merging with a portion of her soul, therefore freeing Jean from the guilt of murder.

Wildstorm Universe related retcons

• After the events of Captain Atom: Armageddon, parts of the WSU were retconned in what was termed a "soft reboot", since not everything was erased. The past stories of some teams and characters, most notably Gen 13, Deathblow and WetWorks were completely restarted, erasing all their previous stories (and connections with other teams and characters) from the history of the Wildstorm Universe. Others, like The Authority and Wildcats, were unaffected, and in a few cases, some characters have vague memories of previous connections with characters that they knew before Armageddon but were involved in the retcon. One character, John Lynch, even seems to know that he (and others) are not the original versions of themselves.

Supreme related retcons

• The character Supreme, a Rob Liefeld creation, went through several retcons during its publication. Alan Moore and later writers have made the character aware of those retcons, which he calls "revisions", and had the character meet alternate versions of himself from previous revisions who told him to expect periodic new revisions. Supreme is currently aware of at least three such revisions (Supreme #41; Supreme #66; Supreme Blue Rose).