Previously known as Earth-AD, the dystopic future conceived by Jack Kirby, Earth-51 is now one of the 52 alternate worlds inside the array of worlds of the DC multiverse. It was established as a parallel universe previously to Flashpoint and featured in Multiversity. Several aspects of Earth A.D. (Earth-51) are occasionally featured as a possible future in the main continuity of the DC multiverse.
Earth-AD originally being believed to be a possible future for Earth where the adventures of Kamandi and OMAC, both Kirby creations, happened. The dystopic future contradicted other DC universe stories including the existence of the Legion of Superheroes, so later they where retconned as an alternate universe.
The story of Earth-AD begins in the future of a parallel dimension. A race of aliens known as the Visionaries forecast the future destruction of Earth in a cataclysm that would come to be known as the Great Disaster. The visionary who discovered this, Prof. Z, addressed the Council of Science and mapped out the precise incidents that would lead to the planet's ruin. He told them that the planet's industrial barons would rise to power and a civil war would ensue which would lead to a calamity known as the "Great Disaster".
Seeking to prevent such a future from coming to pass, the Visionaries came to Earth and established a network known as the Global Peace Agency (GPA). In order to keep their alien origins a secret from Earth's populace, they used cosmetic spray to obscure their features. The people of Earth believed that the Global Peace Agency was made up of world leaders from various nations who intentionally hid their features so as to promote equality between races and cultures. The Global Peace Agency began policing the planet, incarcerating vast numbers of crime lords, corrupt politicians and potential megalomaniacs. Prof. Z however was dubious of their efforts. Though the GPA was making great strides in their efforts to eradicate crime, he still believed that Earth was destined to fall in the Great Disaster.
The One Man Army Corps (OMAC)
One of the GPA's premier scientists, a human named Professor Myron Forest created a powerful satellite computer system called Brother-Eye to help oversee Earth's affairs. He also became provincial in transforming an army stockroom clerk named Buddy Blank into a one-man army corps. Using the name O.M.A.C., Buddy worked in the interests of the Global Peace Agency in fighting Earth's enemies. One of his most dangerous foes was the criminal scientist Doctor Skuba.
The Great Disaster
For all of OMAC's efforts, the Great Disaster could not be averted. Very little is known as to the true causes of the Disaster, but what scant evidence exists points towards a mysterious energy wall known only as the Vortex. Earthquakes and tidal waves erupted all across the globe and the nations of Earth found themselves at the mercy of nuclear Armageddon. Shortly before the final bastions of humanity were to fall, a scientist named Doctor Michael Grant invented a mutagenic chemical known as Cortexin. Although he would not survive long enough to witness the fruits of his labor, the Cortexin drug would succeed in carving out its own legacy in the wake of global annihilation.
Following the Great Disaster, Buddy Blank found himself cut off from the satellite Brother-Eye. He retired as OMAC and set out to eke a new life for himself as ordinary Buddy Blank in this new post-apocalyptic era.
The ambient radiation left behind by the Great Disaster interacted with the Cortexin levels in many of Dr. Grant's laboratory test animals. Over the course of two generations, the animals began to mutate, and their progeny eventually developed anthropomorphic traits including human intellect and the ability to walk upright. With time, these Animal Men inherited the Earth and became the planet's dominant life form. Humanity was left devoid of all culture and social structure, and slowly began to de-evolve into a lesser species (Whether the Cortexin Effect had anything to do with this process is unknown).
The Last Boy on Earth
Decades later, the aging Buddy Blank returned to an army compound located in the ruins of New York City named Command-D. By this time period, the tribes of the Tiger-Men under the rule of Great Caesar had erected the Tiger Empire. Their domain covered most of the Eastern seaboard of the United States. Buddy was careful to conceal himself or else risk becoming prey to the Empire's anti-human initiatives. Buddy sired a child who in turn later gave birth to a son named Kamandi. Kamandi's name was derived from the bunker in which he had been born ( Command-D ).
As it was said, Earth-AD was previously established as a possible future for Earth-1 (DC mainstream earth), confirmed this with time travels for Superman and Batman and sharing adventures with OMAC and Kamandi. When Earth-AD was established as in their own continuity, these appearances were never clarified. Also, Karate kid (from 30th century Legion of Superheroes) also traveled to Earth-AD when he was living in the 20th century. These paradoxes were explained by giving the Kamandi era the alternate earth status.
Post Crisis presence
After the Crisis on Infinite Earths, the original Earth-AD was erased from continuity, both as alternate world and as possible future, with Kamandi being revealed as Tommy Tomorrow, adopted son of Horatio Tomorrow. However, different elements from Earth-AD kept popping in main continuity as in:
- In the sci-fi GN Twilight, the earth people is returning to earth from space to recover the planet from the intelligent animals.
- The adventures of Superboy (Kon-El) in a Kamandi-like landscape and the creation of the Wild men.
- The OMAC project, prior to Infinite Crisis.
- The existence of Brother Eye during Infinite Crisis.
- A new OMAC in New 52.
Countdown & Final Crisis
Earth-51 was highly featured in Countdown weekly, including its destruction (twice); here the great disaster happened in the form of a disease outbreak caused by Karate kid than was the real cause of the mutation of animals into intelligent beings and the involution of humans. The panic would make world leaders launch an unfocused nuclear attack which summed the world into a decade long nuclear winter.
Final Crisis and Multiversity
Earth-AD would return in proper fashion in the last chapter of Final Crisis, where the events of Great Disaster finally happened under the sight of Monitor Nix Uotan who could not save the earth. After Flashpoint, Earth-51, the post 52 and New 52 version, are officially a recreation of the original Earth-AD, filling the space of the destroyed utopic previous Earth-51.
The Kamandi Challenge
Celebrating the Jack Kirby's 100th anniversary, Earth-AD was revisited again in The Kamandi Challenge, which folows the adventure of the last boy on earth in this savage world, with each issue done by a different creative team.
There are also alternate versions for Earth-AD:
- An earth were OMAC stopped the great disaster and avoided the existence of Kamandi future. This OMAC would meet with Earth-AD Kamandi. (Kamandi series)
- An alternate post crisis timeline were OMAC battled in a post apocalyptic land and traveled back in time to became his own grandfather. (John Byrne's OMAC GN)
- An Elseworld version Earth-AD, where Kamandi: At Earth's End and Superman: At Earth's End happens. This Earth-AD is more in the line of the apocalyptic line of movies like Mad Max and The Terminator.
- In Justice League 3000 it was implied than the past of the JL3000 universe includes elements of Earth-51 (Kamandi) and Earth-17 (Atomic Knights).