Here's where I attempt to make an accurate as possible timeline based on the continuity kicked of by Frank Miller's 'The Dark Knight Returns'. This continuity was known as Earth 31 in the multiverse until New52 came around and changed everything. If this continuity exists at all in the new multiverse is unknown at the moment.
These are the comics the Dark Knight Universe is made of:
- Batman: Year One (this was also in canon in the main continuity pre-New52)
- All Star Batman and Robin the Boy Wonder
- Countdown: Arena
- The Dark Knight Returns, The Last Crusade (not out yet)
- The Dark Knight Returns
- The Dark Knight Strikes Again
- The Dark Knight III, Master Race (being published now)
- The Atom #1
- Wonder Woman #1
- Green Lantern #1 (not out yet)
(All comics in chronological order, continuity wise, except for the last three, which are inter cut with the plot of 'Master Race')
I've heard it said that 'Batman/Spawn: War Devil' is a sequel of 'Spawn/Batman' and should therefore also be considered in canon. However, I've found no solid confirmation of this online and I haven't read that comic yet, so I'm leaving it out for the time being. If you're reading this and you do have evidence that 'Batman/Spawn: War Devil' does indeed belong here, please comment so that I can adjust the timeline accordingly. Speaking of Spawn, in his confrontation with Batman his face gets scarred in a way that carries over into Spawn's regular comics. This might drive some to think the entire main continuity of Spawn is in canon with the Dark Knight universe. However, the cause of Spawn's scar has since been retconned as being brought on by somebody else (I forgot who), so we need not worry about that.
As reference on the timeline I'll be using Bruce Wayne's age instead of dates. I'm doing this because the comics take place in the time they came out as opposed to in relation to each other. That's why people have modern mobile phones in the second year of Batman's existence but when he comes out of retirement Ronald Reagan is holding office.
Of course, I can't lay out the events of these comics without spoiling them. So be warned. If you haven't read Batman: Year One or any of the Dark Knight titles yet, I highly recommend you do that first.
While chasing a rabbit on the grounds surrounding Wayne manor, Bruce falls into the cave that would later become the batcave. There, he has a frightening encounter with a large bat, which hisses as it flies straight towards him.
As a doctor, Thomas Wayne's job description includes 'saving lives', something that gathers great admiration from Bruce.
June 26, 10:47 p.m.
Thomas and Martha Wayne are murdered in Bruce Wayne's presence. It's Joe Chill, but it's hinted that Bruce never finds out who the killer is, making most criminals he faces suspect (this could be one of the reasons Miller's Batman is more violent than previous incarnations). The Waynes were just on their way home from having seen 'The Mark of Zorro' (Tyrone Power version), the film leaves a great impression on him.
Bruce leaves Gotham. Starts training at various locations around the world.
Bruce studies forensics.
Bruce is learning an array of martial arts in the far east while also mostly continuing his forensic studies.
(Start 'Batman: Year One')
Bruce returns to Gotham. Then Inspector James Gordon takes residence. His wife Barbara appears to be pregnant, but they're still waiting for the test results (but yeah, she's pregnant). This plot point kind of gets undercut when you include 'All Star Batman and Robin' (hence forward to be addressed as 'ASB&R') in the timeline. There, Barbara Gordon is fifteen (almost sixteen), meaning that she's already a teen during 'Year One'. Since she's obviously retroactively fitted in, there is no mention of her here.
Gordon gets beat up by his colleagues, led by Flass. Gordon in return beats up Flass. Bruce goes on his first night of crime fighting but is unsuccessful (runs into Selina Kyle, who is a prostitute. It's still Frank Miller we're talking about here). Back at Wayne manor he contemplates letting himself bleed out when a bat enters the room. This inspires Bruce to become Batman, he calls Alfred, who has experience as a medic.
Batman and Gordon are getting more successful in their respective fields. GCPD has officially started a hunt for Batman. Gordon has a nice chemistry with detective Sarah Essen.
Batman announces himself to the higher ups of Gotham crime, which includes politicians. The commissioner is not amused and ups the pressure on Gordon to capture Batman.
Gordon devises traps for Batman, but Bruce sees through them. Sarah Essen plays the bait, while Gordon admires her. Crime boss 'The Roman' (Carmine Falcone) is humiliated. Gordon visits Harvey Dent as he suspects him to be Batman.
Gordon and Essen have a moment. Batman and Gordon both try to prevent a runaway truck from hitting a pedestrian. Batman succeeds while Gordon gets knocked out briefly. Gordon and Essen try to arrest Batman which turns into a chase. A wounded Batman takes shelter in an abandoned building. The GCPD tries to burn Batman out by bombing the building, but only succeed in killing innocent homeless people. This excessive force is giving Gordon a crisis of x of sorts. The explosions are attracting the attention of Holly, Selina Kyle's roommate. They go and have a look at the building where an exiting chase is going on. Batman ultimately escapes using a sonar device to make the place swarm with bats.
Selina and Holly quite their job in prostitution by way of Selina knocking out their pimp. Selina exclaims to have a better idea.
Gordon and Essen let the sexual tension between them build up until one night they share a kiss.
Selina becomes Catwoman. Gordon, meanwhile, is going through all kinds of crisis.
Gordon breaks up with Essen. Essen moves to New York.
Commissioner Loeb has photographic evidence with his romantic involvement with Essen, tries to blackmail Gordon. Gordon visits Bruce Wayne, another main suspect in the Batman case. He takes his wife along. On their way back he confesses to his romance with Essen.
James Gordon Jr. is born.
Batman further loosens the Falcone family's grip on the city.
James Gordon Jr. is kidnapped. Bruce Wayne goes after the culprit, who tosses the baby from a bridge. Bruce catches him. "You know, without my glasses, I'm practically blind." Gordon tells Bruce. Complete truth or plausible deniability?
Commissioner Loeb finds himself in hot water.
Gordon becomes commissioner.
The Gordons work on their marriage via therapy.
The first time Gordon and Batman work together is the first appearance of the Joker. He threatens to poison the water supply.
(End 'Year One')
Meets Joker for the first time. Joker poisons Gotham's water supply. This is approximately one year before Dick Grayson first gets training to become Robin.
Bruce uses Gotham sewers as first batcave. To prove to himself he doesn't need wealth for this venture and to practice being Batman in poverty, just in case the day ever comes Bruce Wayne loses his fortune somehow.
Discovers Selina Kyle is Catwoman.
Fictional interpretations of Batman pop up in various media. Including the Adam West television series and a Frank Miller style comic.
Though Gordon and Batman remain friends, Batman's relationship with the GCPD gets worse and has reached a point of being unusually violent by the time of 'ASB&R'.
Inspired by Batman, a fifteen year old Barbara Gordon becomes Batgirl. As discussed before, her sudden appearance on the timeline thoroughly messes with 'Year One'.
Batman's relationship with Gordon takes a hit on account of Batman inspiring copycats. Though Gordon still defends Batman's actions in general.
Gordon's marriage is slipping again and he has resumed his romance with Sarah Essen. Barbara Gordon Sr. is also implied to be in an extramarital affair of sorts.
Batman gets romantically involved with Selina Kyle.
Inspired by Batman, an unnamed Irish lass (she looks like Dinah Lance) becomes Black Canary. Ends up having sex with Batman. Batman dislikes having inspired other vigilantes.
Six months later. While on a date with Vicky Vale, Bruce witnesses the death of the twelve year old Dick Grayson's parents. The murderer, in a direct sense, is a thug named Jocko-boy Vanzetti. Yet the orders ultimately come from the Joker. Bruce takes in Dick Grayson.
The recently formed Justice disagrees with Batman's methods and discuss how to deal with him. Wonder Woman proposes to kill him while Superman thinks he should be taken to the police (which, in Gotham, isn't that much different from Wonder Woman's proposal).
Bruce trains Dick Grayon to become Robin. Dick can choose his own persona and decides to become 'Hood', after Robin Hood. However, Batman doesn't like the actual hood on Dick's costume, as it is ill suited for fights, and declares "Loose the hood, you're Robin".
Green Lantern (Hal Jordan) visits Gotham and tries to reason with Batman, but ends up fighting both him and Robin, who is on his first assignment as such. Robin loses control over his rage and nearly kills Green Lantern. Bruce takes this as a sign that he had been too rough and that Dick should have been given the time to grieve. They visit the Grayson grave.
Gordon meets Batman at the docks, further cementing in the fact that Batman is on really bad terms with the rest of the force. Considering the violent behavior Batman and Gotham police have shown towards each other, I'd say avoiding the famous rooftop for now is a good call.
Batgirl starts a riot, but she's in way over her head. She ends up getting arrested and Gordon now knows of her secret identity. Barbara Gordon Sr. meanwhile gets into a car crash caused by her excessive drinking. Basically, Gordon is having a pretty shitty night. Barbara Jr. says he should call Sarah Essen, and he does.
Cautiously starts friendship with Superman. Ultimately even teams up with him in the style of the 'World's Finest' comics.
Has a battle and then a team up with Spawn. There's no mention of Dick, perhaps things are already getting sour by this point (see next paragraph)?
Fires Dick Grayson. They have a falling out. Whatever happened to cause this has caused Bruce to call Dick a coward and incompetent.
Bruce takes on a second Robin, Jason Todd.
Large riots occur in Gotham. Bruce modifies Batmobile to resemble tank.
Becomes member of the JLA, develops friendship with Hal Jordan.
Two Face's last crime before getting locked in Arkham for a decade involves the kidnapping of Siamese twins.
JLA is pressured into disbanding. Most members of the JLA retire. Superman goes to work for the government, and Batman continues to fight crime in Gotham. Hal Jordan, by then Batman's best friend in the superhero community, retires to space. Batman unsuccessfully pleads for him to stay.
Joker kills Jason Todd, Batman Retires. Many superheroes are relieved, as they disagree with Batman's modus operandi. The upcoming 'The Dark Knight Returns, The Last Crusade' delves deeper into this story.
Joker finds little joy in his crimes without having Batman to duel with, falls into catatonic state. He gets imprisoned in Arkham.
Bruce meets Dick, but old wounds have not healed. They part ways on bad terms.
(Start 'The Dark Knight Returns')
Somewhere in between 'ASB&R' and this comic Jim Gordon has divorced Barbara and Wed Sarah.
Bruce meets up with Gordon to (herdenk) the tenth anniversary of Batman's retirement. Gordon is fully aware if Batman's identity by then and the two reminisce. Following the event Bruce runs into two teen members of a new gang called 'the Mutants'. He is attacked, but wards it off. Bruce begins to sleepwalk, ending up in the batcave and even goes as far as unknowingly shave off his moustache. When he watches television one night he comes across a network that is airing 'The Mark of Zorro', which makes him relive the night of his parent's murder. In inner monologues he speaks of Batman as a separate entity, waiting ever more impatiently to come out. Then, on the first rainy night following a heat wave, the Dark Knight returns.
Two Face is released from Arkham, as he is considered fully rehabilitated. Sadly, he falls victim to his alter ego once again and must face of against Batman.
Joker, upon seeing the return of Batman play out on the news, awakes from his catatonic state and with the help of a questionable x, gets released too. Once out, he kills hundreds and in the final confrontation with Batman, kills himself, framing Batman.
Bruce reluctantly takes on a new Robin; Carrie Kelly.
The Mutant Gangs gets disbanded and reformed by Batman. A large portion of them decide to become Batman-inspired vigilantes, calling themselves the Sons of Batman.
The government (Ronald Reagan personally, in fact) sends Superman to stop Batman. Superman tries to reason, but Bruce won't budge. They fight (Green Arrow aides Bruce) and Bruce appears to die. This was just a trick, however.
Together with Green Arrow, Bruce decides to train the Sons of Batman and Carrie Kelly. The new generation of vigilantes.
(End 'The Dark Knight Returns')
Secretly training the Sons of Batman and Carrie Kelly.
(Start 'The Dark Knight Strikes Back')
"After going underground, Bruce Wayne and his young sidekick Carrie Kelly, now Catgirl, train an army of "batboys" to save the world from a "police-state" dictatorship led by Lex Luthor. In a series of raids on government facilities, Batman's soldiers release from captivity other superheroes including: the Atom (trapped for years in a petri dish), Flash (forced to run on a treadmill to provide America with free power), and Plastic Man (now insane and trapped in Arkham). Elongated Man is recruited from his job as a commercial spokesman and Green Arrow is working with Batman. Luthor responds by sending a genetically-superpowered man who resembles the Joker to kill as many superheroes as possible. Batman, with help from his allies, manages to take Luthor down, and Luthor is killed by the son of Hawkman, who had been killed earlier on by Luthor.
As he returns home, Batman receives a communication from Carrie, who is being attacked by the new Joker. Batman rushes to her aid and recognises the man as Dick, who has been genetically manipulated to possess a powerful healing factor, but has been driven insane. Batman shows nothing but contempt for his former sidekick and plans his death the moment they face each other. Batman hurls himself and Dick into a miles-deep crevasse filled with lava and blows up the entire cave, igniting an underground volcano and destroying everything. Dick falls into the lava and is killed, but Batman is saved by Superman at the last moment and brought to Carrie in the Batmobile."
(End 'The Dark Knight Strikes Back'')
Sometime in these years Superman becomes encapsuled in Ice inside the frozen over fortress of solitude, or Superman dies, after which the fortress freezes over at some point. It's not entirely clear at the moment. Not to me anyway.
(Start 'The Dark Knight III, The Master Race')
Reports of Batman are causing a stir in the media and political landscape. When arrested, it turns out to be Carrie Kelly in the suit.
Superman's daughter. Lara, visits Superman's body in the fortress of solitude. There, she finds the bottled city of Kandor, which has the words 'help us' written on the side. She takes the city to Dr. Palmer, the Atom, explaining that they no longer wish to be small. Dr. Palmer helps in getting the city's inhabitants to full size. After accomplishing this, he finds a large portion of the Kryptonians to be massacred. Dr. Palmer has been dubbel crossed. Baal, on of the two Kryptonians Dr. Palmer has been communicating with throughout the process, kills him.