A former Scribe of the Brotherhood of Steel, Elijah defied convention and rose to the rank of the Chapter's Elder, an honor usually reserved for Paladins and Knights. His leadership style was considered unorthodox, as instead of simply gathering pre-War weapons technology and hoarding it, he would dispatch Scribes to retrieve farming equipment and other beneficial technology, believing that the Brotherhood would be unable to survive without providing tech to the people of the wastes, gaining their favor and with it more recruits. His practices were not continued by his successor, but he did pass his ideas onto his protégée, Veronica Santangelo, despite previously separating Veronica from her lover. Despite his intellect and forward thinking, Elijah revealed himself in time to be a brutally pragmatic and altogether unpleasant man.
It was not until the war with the New California Republic, dubbed Operation: Sunburst by the NCR, that Elijah's true nature became apparent to the rest of the Brotherhood. It was clear that the Brotherhood was on the losing end of the conflict, but Elijah refused to accept defeat and became obsessed with finding the technology required to defeat the NCR. Operating from the Brotherhood's HELIOS One base, he sent Paladins out on a number of missions that could be considered tactically questionable in efforts to secure vital technologies he was adamant would swing things in their favor. He eventually discovered that the secret to victory lay on his own doorstep, with the ARCHIMEDES II weapon. Though the Brotherhood position was tactically unsustainable, Elijah felt that if he could just get ARCHIMEDES functional, the NCR could finally be pushed back. He stubbornly refused to give ground, but salvation never came, and one day Elijah simply disappeared into the wastes without a warning to anyone, not even Veronica, and was assumed to have deserted the Brotherhood. His successor, Nolan McNamara, wasted no time in gathering up the few that survived the battle at the facility and retreating to Hidden Valley.
But Elijah had not truly abandoned the Brotherhood, nor his desire to see it dominant, but had in fact left to find new technologies that would save them - to find what he believed was "one of the greatest treasures of the Old World." For Elijah the Brotherhood was doomed; they needed to begin again and he would do whatever was needed, no matter how morally questionable, to ensure that came to pass. He traveled throughout the Wasteland, going as far as the Divide and spending time among the Ciphers.
Eventually, Elijah stumbled across the Big MT in his travels, where he found an incredible amount of rare pre-War technology. Captured temporarily by the Think tank upon his arrival, he managed to escape in seconds, much to the shock of the brain bots. In the great expanse of Big Mountain, Elijah ran into another human, a courier, who spoke to him of the legend of the Sierra Madre. Making his way to Little Yangtze, he experimented on the survivors of the prison camp with explosive collars while, curiosity getting the better of him, seeking out the radio frequency until finally tracking down a faint broadcast. Avoiding the local robots and suffering from migraines through the overuse of Mentats, Elijah fine-tuned both the collars and the radio signal. Now, with the location of the mythical casino and his collars ready, his grand plan to defeat the New California Republic was ever so close to fruition.
However, the trail of crimes he had left across the wastes in the years preceding his arrival had not gone unnoticed, and a hardline faction of the Brotherhood soon dispatched assassins to stop him. Christine Royce was one of them. As the think tank sent robots to contain him and, catching a glimmer from a sniper scope, Elijah instinctively sensed the worst. He held out in the tower for a while, sniping the Think Tank's robots with his Tesla Cannon as they funneled through. Then, strategically detonating his subjects' collars to make his getaway as she attempted her assassination, Christine was defeated, becoming a subject for medical experimentation as she was dragged away to the Y-17 medical facility. Cybernetic modifications, one of the many Old World horrors left in the Big Empty, were implanted in her brain that damaged her perceptions of the world around her. Hacking into the think tank mainframe as the Big MT's robots closed in, Elijah fried Doctor 8's voice module and rerouted Doctor O's processors to take control of the train network. Via remote control, he directed a train into one of the tunnels, creating a path for his escape through the wreckage. Leaving his retrofitted LAER rifles and jury-rigged Tesla cannon behind, he then set off towards the Sierra Madre with a Gauss rifle, several explosive collars, a Holorifle and, crucially, the knowledge that could make the Mojave his, and his alone.
To prepare for his expedition, he renovated an abandoned Brotherhood of Steel bunker as a base of operations in the Mojave, setting it up ready for when he managed to get his hands on the technologies it offered. In making round-trips around the Sierra Madre to his bunker, he performed analysis of the Cloud and the Sierra Madre's environment. Once ready to go to the Sierra Madre, he left a final message for Veronica in the event he did not return.
Upon reaching the Sierra Madre, he found everything that he had hoped for and more. The Cloud had somehow preserved the pristine nature of the casino and prevented it from decaying in all its years of disuse, in addition to serving as a deadly deterrent to potential intruders. He marveled at the casino's automated security systems - the invulnerable holograms, perfected versions of the technology he had found at the Big Empty. A single one of these holograms, deployed in the right place, would become a one-man army, massively powerful and almost impossible to defeat with conventional weapons. But the potential of these paled in comparison to a relatively innocuous technology: the Sierra Madre vending machines. These machines functioned as a sort of molecular assembler, taking Sierra Madre chips and using the raw material in their composition to assemble various alcohols and clothes as rewards for gamblers. The potential for these had already been partially realized before the war, as medical staff and construction crews had used them to generate medical supplies and explosives. But Elijah had grander ideas. He could use the machines to create any object he desired, and provide the same luxury to the people of the wasteland. He could create a new world where the very concept of "need" was eliminated, a new world with the Brotherhood of Steel at its head and the Sierra Madre at its heart.
However, Elijah also found that he could not unlock the secrets of the casino's vault alone. He used his explosive collars to coerce captives into trapping other fortune seekers lured by the Sierra Madre's signal, forming a chain that eventually grew into teams conscripted to do Elijah's bidding - or die. Eventually he found a new way of starting the chain in the form of Dog, a nightkin whose overwhelming need for a master figure allowed Elijah to bend him easily to his will. Human nature got the better of these teams though, and as soon as they became close to the treasure they all felt they could take it for themselves, inevitably turning on one another. One team managed to actually get Elijah into the heart of the casino, but after their deaths, Elijah found himself trapped and alone. So he modified the signals controlling the collars to add an extra condition: if one person died, they all would die. Unable to communicate with Dog and the outside, Elijah assumed this would be his end, until Dog, automatically acting on orders given to him long ago, brought to the casino a prisoner with a Pip-Boy 3000, someone with whom Elijah was capable of communicating. Elijah would be free to go, assuming he could bear to leave behind the casino and all its secrets.
In the years that followed, the legend of the Sierra Madre faded, and there were no... new visitors to the city. Years later, when a mysterious blood red cloud began to roll across the Mojave, then West toward the Republic, no one knew where it had come from. Only that it brought death in its wake. Attempts to find the source of the toxic cloud failed. The Mojave was cut off. Through the Cloud, lights were seen from HELIOS One. There were stories of ghosts immune to gunfire, who struck down anyone they saw with rays of light. The last chapter of the Mojave came when a modified REPCONN rocket struck Hoover Dam, releasing a blood-red cloud, killing all stationed there. All attempts to penetrate the Cloud and re-take the Dam failed, and both the NCR and Legion finally turned away from it, citing the place as cursed. In the years that followed, communities across the West began to die as traces of the Cloud began to drift over lands held by the NCR.¹ Only two remained alive in the depths of the Cloud, at the Sierra Madre, waiting for their new world to begin again.
Elijah meets his end abruptly in the Vault, where he fights the Courier and falls in single combat. His corpse, along with that of Frederick Sinclair, lies in the now totally inaccessible Vault forever.
Elijah is locked in the Vault
Elijah, lured by the promise of the Sierra Madre, cannot escape. Once inside the vault, the casino does not let go. When Elijah finally passes away, the casino creates a new hologram to walk with the other ghosts that fill its casino. It is a pre-programmed homage intended for another. It assumes a new meaning in the likeness of Elijah. A means of allowing even the dead to begin again.
* Elijah carries two Gauss rifles; a normal one which he will drop upon death, and a special non-player character-only version which he will use if his regular Gauss rifle is disarmed from him. Elijah's non-player character-only Gauss rifle is coded as a companion weapon; it doesn't use ammunition, cannot be disarmed, and cannot be looted.
Elijah claims to have made more holorifles, but he doesn't use any, nor are there any others in Dead Money. However, by listening to his broadcast while in Salida del Sol, the Courier can overhear him bemoan giving up the holorifle. This makes it likely that his initial claim, similar to the one made about Pip-Boys, is simply Elijah trying to belittle the Courier.
If he is trapped in the Sierra Madre Vault, he can be heard mumbling to himself on his radio signal.
If the Courier has exhausted all dialogue about him with Veronica, they can bring her up in conversation in the Vault's chamber.
Speaking to Veronica about Elijah with Dead Money installed, before leaving for the Sierra Madre, also adds additional dialogue with Elijah.
Elijah apparently has arthritis, as he can be heard mumbling to himself about his "damn arthritis".
He has high amount of Hit Points for a human character, more than most companions with the exception of Dog and God and Lily Bowen, and a powerful weapon, the Gauss rifle.
Elijah has a Pip-Boy himself, despite the fact that he belittles the Courier's use of it on several occasions. This is best seen with a Stealth Boy, and closely looking while inside the vault.
It can be assumed that Elijah is an exceptionally hardy man; despite a combination of arthritis, Mentat addiction-induced migraines, drinking, smoking, and old age, he is not only still alive, but mobile and combat-ready, as he has obviously travelled many hundreds of miles in his quest to restore the Brotherhood and is no pushover when confronted in the Sierra Madre Vault.
When talking to Brotherhood Paladins in the Hidden Valley bunker they will sometimes talk about Elijah and how he used to be their elder.
"That thing on your wrist - it's a convenience. It tells you where to go, what to do, dulls your brain.. It may have helped you find the Sierra Madre broadcast, but it's just as much a crutch today as it was in the Old World."