The Wildstorm Universe started as part of the shared universe of Image Comics, but eventually it developted its own continuity. A detailed story of the imprint can be seen here.
The original continuity with details tied to other Images properties was retconed as it was built its own continuity and eventually dropped them as the line reach maturity.
The Wildstorm universe was a place with a more violent landscape were super being are watched with distrust and where secret agencies and conspiracies work in the creation of the ultimate supersoldier and the control of the world.
The history of the Wildstorm universe was heavly influenced by two alien races in intergalactic conflict stranded on earth since prehistoric times: Kherubim and Daemonites, which helped to built civilization and legends and later where the base for the birth of the superbeings, by breed with the natives humans.
Most of the superhumans of Kherubim ancestry, as others notable post humans woudl join for the first time in the famous Team One. However Team One ended abruptly and tragically when Majestros add to killed John Colt. The members of Team One would not be reunited again but several of them would end as pivotal elements of the several superteams than appeared later.
By the end of the XX century, the number of posthumans were so high than the UN approved the existence of Stormwatch, an international task force to intervine in post human caused crisis, being their main source of problems the terrorist island of Gamorra, a rogue nation where powered criminals and fringe illegal technology coexisted . Meanwhile, the Kherubim would continued their millenia old war through new different teams, such as the WildCATS, an undercover team backed by the Halo Corporation. Other humans would gain superpowers thanks to genetic manipulation, including the exposure to comet induced radiations, making them gen-active and capable to transmite this trait to their children, as with Team 7 and Gen13. Other anomalies as supernatural beings were dealt with severity, as the Wetworks demostrate their military experience against vampires and werewolves.
The first official crossover of the Wildstorm universe was Wildstorm rising. When a lost spaceship from daemonite origin was discovered, three daemonites lords (Defile, Helspont and Hightower) fought among them to see who could keep the ship for himself. The heroes of the different teams would see themselves involved at different levels, from directly affected (as the WildCATS) to the anecdotical (Gen13). Eventually the WildCATs would reach to the ship and launched it back home, with all the other heroes believe them dead. From this event and further, the Wildstorm universe became more independent from his original Image shared universe.
The WildCATs would travel to their homeplanet only to discover than the war ended millenia ago and they never were rescued for their people because the earth was too much far away. This will have lasting effect in the members of the team when they decided return home.
Fire from Heaven
When the members of Team 7 discovered than they were dying because of their own powers given by Miles Craven, they decide than wanted Craven dead before them. Craven than put himself under the protection of Kaizen Gamorra, who asked for the protection of the Stormwatch team against the superpowered invasors. Gamorra and Craven were in secret experimenting with the Sigma clone, a being from an alternate universe and the source por powers of the Team 7 and every gen-active. However these experiments attracted the atention of Damocles, an extradimensional being, destructor of realities, obsessed with the destruction of Sigma, his enemy, rebirth in the earth as the son of Dr. Tsung. Damocles send his herald, the Sword to prepare his arrival. Eventually the situation in Gamorra was resolved but the heroes had to travel to the moon where Damocles had built an engine to push the moon against the earth and use the energy to travel to another universe. Only the sacrifice of Deathblow saved the earth.
Fire from Heaven left as consecuense the knowledge of the Wildstorm universe was composed by several unknown alternate universes.
Path to the Authority
After those events, Weatherman Henry Bendix reorganizated Stormwatch into different teams: Stormforce, with standart soldiers; Stormwatch Red, with superpowered agents, to act as offensive force and Stormwatch Black, to undercover operations and unknnown to the rest of the team or to UN administration. to operate more efficently against any posthuman menaces, which put him in conflict with several world powers, by interfering with their secret operations and violating several international laws. Even his officers doubted of his intentions. When the Changers, a team of old post humans, appeared with intentions to save the planet of goverment corruption, Bendix used the Stormwatch operatives to kill them summarily. This caused the insurrection of Jackson King and Jenny Sparks, who fought against Bendix and apparentelly caused his demise. King was designed new Weatherman and offered a position to Sparks and the rest of the Black team but they declined.
The tenure of King as Weatherman was shortlived and ended tragically when Skywatch-one was invaded by aliens xenomorphs, causing the death of almost all the posthumans operatives. Only the intervention of the WildCATs saved the surviving officers. But the damage was done. Without a budget to support the team Stormwatch was clausured by the UN. Unknown to them, Jenny Sparks had other plans...
Change the World
Commanding a new team, the Authority, Jenny Sparks changed the superhero paradigm. It was not enough fight against villains, they have the power to change the world. After recruit a team of powerful posthumans and using a shiftship capable to travel througt dimensions, Sparks and her team, the Authority, protected the earth against superterrorists, parallel invasors and God. Sparks died killing the last menace and was suceded as leader by Jack Hawksmoor, who implemented an even more agressive agenda. The example of Sparks however was followed by the Wildcats who also choose follow that path but through more subtle ways, as introducing alien technology in the mundane live of the earth people. Working at a different level, Jackson King would work in the dark with his own team know as the Monarchy and others, like Ben Santini, reacted negativelly under the idea of a pack of superpowered bulllies and as new Weatherman, stood to keep the Authority in line with his own team Achilles.
An incident with alien technology of the V'gil, incited by TAO, caused than the fragile balance of superpowers to fall apart. Tired of the burocracy and pettyness of the US goverment, the Authority choose to take over the country and arresting the President as the mind behind the disaster. After his execution, the Authority dealt with the other superhumans in active. Team Achilles went underground and the WildCATs saw the coup as a brief political unrest, soon to be overlooked. The end of the Authority as comanding the US goverment would be orchestrated by a returned Henry Bendix, who break up the Authority and give back the country to the previous politics. It would take several years for the authority to heal and be a team again, after their fail. However the team was reunited again and ready to keep safe the 21st century.
Things would complicate for the heroes of the Wildstorm universe when Captain Atom, a being of another group of universes landed on earth, fused with a fragment of WildCATs member Void. Mr. Majestic, who already had traveled to Captain Atom reality discovered than soon Atom would detonate, destroying the universe. Searching a way to save the universe, the Authority choose to kill Atom. Unknown to them, killing Atom it would be the cause of the end of the universe. After discovering this fact, Majestic tried to warn the Authority and stopped of kill the Captain, but they didn't wanted to hear him. When they tried to kill him, the Captain began to meltdown. Uncapable of stop the process,, Majestic and the Doctor were ready to die. However, the new Void appeared and heal the Captain, by removing the void fragment. Without the fragment, Captain Atom was capable of return to his earth. But in the Wildstorm Universe, Void caused a soft reboot of the reality, wich changed the personal history of several characters. Beyond that, the universe lived again, same as before. Around this time, the Wildstorm Universe was considered as one of the DC alternate universes, as earth-50.
Armageddon: World's End
The destiny of the earth was determined. After visiting several heroes and warning them about an impeding disaster, Void disappeared. Several SPBs (superpowered beings) reappeared and a mysterious program known as Number of the Beast was revealed: a secret facility were the US army had several SPBs in an apocaliptic biblical setting. However they commit a mistake: they connect the remains of the High (of the changers) to the machine and because of that, the posthumans awake from their slumber to discover they had lost several decades of their lives. Alerted by this event, the US army activated his back up plan: an army of High clones, the Reapers, to strike back. However what they didn't count it was than one of the scientific in charge of the project was a daemonite and the biblic imaginery inside the clones pushed them to cause a catastrophic event: the axis earth was changed and millions of persons died. Even the heroes were affected: the Carrier crashed in London, several posthumans died, new post humans appeared and new alliances were forged. In a post apocaliptic landscape, the heroes of the earth had to change their method if they want save mankind.
Even in this context, new dangers appeared: the Redblade, a millenia old kherubim ship and its crew reach earth, ready to waste what it left of the planet. The surviving heroes worked together to stop the aliens, but divided forces when the Carrier was reactivated and travelled back to its home.
The Authority (the Carrier team) had to deal with the dangers of an uncontrollable travel meanwhile the WildCATs (earth team) had to fight against the menaces as the lost kherubims and crazy magicians, who wanted absorb the life of earth itself. Eventually the Carrier team could return earth, and the earth team defeated a mad Jeremiah Cain, the worst dangers ended.
The heroes then started to help the world in a more proactive way to rebuilt the world or even built a better one. The Wildstorm universe (and imprint) ended in this form with its continuous publication.
New52 & Convergence.
During the miniseries Flashpoint,several elementsof the Wildstorm universe made act of present, which ended with theWildstorm universe being fused to the mainDCU, in the same fashion than previous imprints (Charlton, Fawcett, Quality) integrated their characters to to the main DCU.
Described as an alternate timeline in Flashpoint 5, the Wildstorm universe was fused with the New Earth to create a Prime Earth, which includes some traits of the Wildstorm universe. Among them where the existence of a secret Stormwatch organization, team like Team 7 than included several DCU membersandmany worlds conspiracies hidding supernatural happenings. Some elements integrated more sucessfully than others.
In Convergence a most earlier version of the original Wildstorm character make an appearance fighting against the DC's Zero Hour era characters. They eventually were returned to their proper reality by Telos.
DC Rebirth and 25th Annivesary
As consecuense of Rebirth in DC, the Wildstorm references were eventually retconned out of the most of the DC Prime universe.
The Wildstorm universewas not forgoten however. An issue with stories set before and after the world's end event were reunited in the hardcover collection for the 25th anniversary of the line. The most relevant issue was about Majestic revisiting a reunion of the leaders of the different factions of the WIldstom super teams (Authority, WildCATs and StormWatch) dealing with their plans for the future.
The Wild Storm
In 2016, Warren Ellis (from The Authority fame),redefined the Wildstorm universe, creating a new version of this universe, more sci-fi oriented and which exists in their own reality. This new universe presents paradoxically some DCU characters and traitswhere they are minor elements to the Wildstorm big picture.
Now Skywatch and I.O. are secret organizations sharing the control of the universe and experimenting with alien technologies in an unsusoected population. But unknown to the members of these organizations, there are several wildcards, including millenia old aliens living among humans, a new generation of hybrids and a new force with the authority to control them.