Allan Quatermain was born in England in the early 19th century. By the 1850s, he became an explorer and big game hunter, preferring to spend most of his time in the plains of Africa, rather than his native England. During many of Allan's early adventures, he was accompanied by his friend Sir Henry Curtis, as well as his faithful ally Umslopogaas. In 1886, Allan participated in a harrowing adventure in the lost kingdom of Zu-Vendis - a journey that cost Umslopogaas his life. Quatermain witnessed Umslopogaas' final battle against his hated foe Lord Nasta. His friend's death pained him so much, that he decided to retire from the life of a big game hunter. Conspiring with his biographer H. Rider Haggard, Quatermain faked his own demise and lived a life of seclusion. He later told his friend Luna Holmes-Ragnall that he faked his death, because the world would not wish to see the image of a heroic Quatermain sullied by the passage of time, "grey and doddering, pruning his roses in some leaden suburb".
Living the life of a recluse, Quatermain developed a taste for a rare African herb known as Taduki. Taduki produced psychoactive symptoms and provided the imbiber with a perception of their past lives. By 1889, the chief source of Taduki was the English woman Lady Luna Holmes-Ragnall. Allan visited Lady Ragnall, who herself, had become a wasted shell of a woman due to her addiction to Taduki. She provided Allan with a sample, and upon inhaling the vapors from the drug, Allan found his conscious mind torn from his body, and propelled into what he referred to as the "sundered veil". In actuality, Allan's astral self had been pulled into the time stream, whereupon he met other adventurers who were likewise trapped beyond the veil. Allan met John Carter, a rugged Confederate soldier from the United States as well as Carter's 20th century descendant, the Rhode Island scholar Randolph Carter. Allan soon learned that the being responsible for pulling him into the time stream was an enigmatic man from his own era, known only as the Time Traveler. The Time Traveler invented a time machine, and brought all three men to a point in time in Earth's far-distant future. In this future setting, England was little more than a barren landscape. The only structure to be found was the Time Traveler's base of operations, a gigantic Sphinx that had somehow withstood the ravages of time. The Time Traveler needed the help of these men in combating an alien existential evil that existed beyond the boundaries of explanation. These beings were known only as the Great Old Ones. Through the course of this episode, Allan experienced visions of his own future, and knew that he was one day fated to meet a woman named Mina and to join a League of heroes in service to the crown. Allan eventually returned to his own time period and physical body, but not without paying an exacting price. Upon his return, Allan was possessed by the spirit of Ithaqua, one of these Great Old Ones. Under Ithaqua's domination, Quatermain killed Lady Ragnall, but Ragnall's maidservant Marisa was able to exorcise the Old One from Allan's body before he could cause any more damage. 
The entire affair greatly traumatized Allan. Leaving England, he took up residence in Cairo, where became hopelessly addicted to opium. In 1898, Allan found his visions coming to fruition. A woman named Mina Murray found him in an opium den and told him that England required his services. Although his health and sobriety were both in great decline, Allan managed to save Mina's life when a band of surly Arabs attempted to ravish her. Knowing that he was no longer safe in Cairo, Allan reluctantly agreed to assist Miss Murray. She introduced him to the legendary "science-pirate" Captain Nemo, and brought him on board Nemo's ship, the Nautilus. At the behest of British Secret Service liaison Campion Bond, Allan Quatermain became a member of an elite group of special agents dubbed the League of Extraordinary Gentlemen. 
Allan's first mission with the League was to accompany Mina to Paris, France to meet a retired private investigator named C. Auguste Dupin. Dupin was to assist them in finding a London physician named Henry Jekyll, who had been reported seen in Paris in recent months. Neither Mina nor Allan knew why Campion Bond was interested in finding Doctor Jekyll, but they soon discovered that Jekyll possessed the ability to harness his darker passions, physically transforming into the monstrous Edward Hyde. Allan and Mina baited Jekyll into a trap, forcing him to transform before their eyes. Hyde attacked Mina, but Dupin kept him at bay by shooting his ear off. It was Allan however, who finally subdued the brute by forcing him to drink an entire bottle of laudanum. With the mission completed, Allan and the others brought Hyde back to London. 
The team's second mission required Allan to go undercover. Mina and he adopted the guise of a married couple and began investigating strange occurrences taking place at Miss Rosa Coote's Academy for Wayward Gentlewomen in Edmonton. Three women at the Academy found themselves with child, with no evidence of a father figure. They blamed their conditions on some invisible phantasm, though headmistress Rosa Coote believed their situations to be a result of immaculate conception. They soon learned that this invisible phantasm was in reality an unscrupulous man named Hawley Griffin. Griffin had developed a formula, which permanently rendered him invisible. Allan and Mina encountered Griffin and struggled with him, but it was Mina who finally exposed the charlatan for what he was. They brought him back to England for observation, but he soon joined the League's ranks along with Edward Hyde. 
With the addition of the team's newest members, Allan and the rest of the League embarked on a mission that threatened all of England. An oriental crime lord known as Fu Manchu had stolen a supply of material with anti-gravitic properties called Cavorite. Allan and Henry Jekyll went into the Limehouse district to gather information on Fu Manchu (whom Allan referred to as a "Demon Doctor"). He caught a brief glimpse of Fu Manchu at an opium den called Shanghai Charlie's. The crime lord's visage bothered Quatermain greatly, and he reported back to the rest of the League. Mina on the other hand, had discovered where Fu Manchu's operatives were storing the Cavorite. It was located in an abandoned channel passage that ran beneath the Rotherhithe bridge and the Thames. The only known entranceway was through a homeless shelter. Once again, Allan and Mina posed as a married couple seeking a place to stay. They found the passageway, which led them to the center of Fu Manchu's operation. With some assistance from Edward Hyde and the Invisible Man, they were able to steal the Cavorite. As Fu Manchu's men surrounded them, Allan blasted a hole through the glass roof of the tunnel with his elephant gun. As river water poured in, Mina activated the Cavorite and it pulled them all upwards through the water to the surface where the Nautilus promptly scooped them up. 
- Hand-to-Hand Combat (Basic): In his prime, Allan Quatermain was an able-bodied pugilist, often forced to rely upon his fighting skills while adventuring in Africa. As he aged and his health deteriorated, Allan's fighting skills waned. In June of 1898, Mina Murray commented that he was "overrated as a pugilist".
- Tracking: Allan Quatermain was a master at tracking animals for sport and profit. He once led Sir George and Henry Curtis on an expedition to find the fabled diamond mines of King Solomon.
- Firearms: Allan is extremely proficient in the use of hunting rifles.
- Allan Quatermain is the creation of novelist Sir Henry Rider Haggard and first appeared in the 1885 novel, King Solomon's Mines. Although most of the history relating to the literary Quatermain may be considered authoritative, it should be noted that Allan's adventures in Africa have been exaggerated by Rider's accounts, who himself, exists within the same reality as that of his creation. 
- Allan is chemically dependent on opium as well as the rare Taduki plant.
- Allan wore a chainmail shirt beneath his regular clothing to protect him from injury. 
- 13 Appearances of Allan Quatermain (Earth-ABC)
- 7 Images featuring Allan Quatermain (Earth-ABC)
- 1 Quotations by or about Allan Quatermain (Earth-ABC)
- Character Gallery: Allan Quatermain (Earth-ABC)
- ↑ League of Extraordinary Gentlemen (Volume 1) #1-6; Allan and the Sundered Veil (illustrated text story)
- ↑ League of Extraordinary Gentlemen (Volume 1) #1
- ↑ League of Extraordinary Gentlemen (Volume 1) #1-2
- ↑ League of Extraordinary Gentlemen (Volume 1) #2
- ↑ League of Extraordinary Gentlemen (Volume 1) #3-4
- ↑ League of Extraordinary Gentlemen (Volume 1) #1; Allan and the Sundered Veil
- ↑ League of Extraordinary Gentlemen (Volume 1) #4