Desmond Miles

In the first game in the series, Desmond leads a simple life as a bartender in New York City.[3] In order to hide his identity, he lives under assumed names and uses only cash to protect himself. However, because his ancestors were well-known Assassins, he is eventually tracked down and captured by Abstergo Industries, a front for the modern-day Templar Order.[3] Once inside Abstergo's facility in Rome, Italy, Desmond is forced to enter the Animus, which allows him to relive the memories of his ancestors stored in his DNA.[3] It enables him to separate Desmond's consciousness from his body and to infuse his mind with his ancestors,[3] all under the watch of Abstergo scientist Dr. Warren Vidic and his assistant Lucy Stillman.[27] They explain that they are searching the memories of Desmond's ancestors, specifically those of Altaïr Ibn-La'Ahad (1165–1257; Syria),[3] for specific information, which they refuse to disclose.[28] Without much choice, Desmond begrudgingly agrees to help them.

After recovering the information for which Vidic was searching—a map showing the locations of various "Pieces of Eden", artifacts with the power to control humans believed to have been created by a Precursor race— Abstergo's executives order Desmond to be killed. Lucy's quick thinking saves him, as she persuades Vidic to keep him alive until they know he is of no further use. Upon returning to his room, Desmond, suffering from the "Bleeding Effect" due to prolonged exposure to the Animus, discovers he has gained Altaïr's "Eagle Vision". This allows him to discern friend from foe and to read cryptic messages written on walls and floors by Subject 16, the previous Animus test subject that Lucy and Vidic occasionally mention.

Assassin's Creed II continues from where the first game left off, as Desmond escapes from the Abstergo facility with the help of Lucy, who is an undercover Assassin in Abstergo. He enters the Animus 2.0, supervised by Lucy and her team of assassins Shaun Hastings and Rebecca Crane, to be quickly trained as an Assassin via the Bleeding Effect. He relives the memories of Ezio Auditore da Firenze (1459-1524; Italy),[3] his ancestor from the Renaissance. After successfully navigating Ezio's early memories, Desmond is extracted from the Animus to avoid the mental degradation that Subject 16 suffered as a side-effect of the Bleeding Effect. Shortly after extraction, Desmond flashes back to one of Altaïr's memories, despite not being linked to the Animus. Desmond learns of Altaïr's lover Maria Thorpe, a former Templar used as a decoy by Robert de Sablé. As Altaïr leaves, Desmond wonders why he is not following the Assassin; instead, he moves towards Maria and enters her womb, showing that Altaïr's child— another of Desmond's ancestors—has just been conceived.

After spending more time in Animus 2.0, Desmond begins to adjust to his newly developed skills and becomes agile and expert fighter, similarly to Ezio. The last segment of Ezio's memories brings an astonished Ezio and Desmond to a futuristic chamber underneath the Sistine Chapel, where they are met by a hologram of Minerva, a member of the Precursor race that created humanity and the Pieces of Eden known as the First Civilization. Minerva addresses Desmond by name, knowing that he is reliving Ezio's memories, and talks about a cataclysm that wiped ou most of her race tens of thousands of years ago, and which is set to occur again by the end of that year if Desmond does not prevent it. Desmond is then pulled from the Animus as Abstergo discovers their hideout. The team escapes; Desmond using the skills acquired from the Bleeding Effect to repel Abstergo's forces. Desmond enters the Animus while in transit, knowing Ezio and perhaps Subject 16 may have the answers they seek.

In Assassin's Creed: Brotherhood, Desmond, Lucy, Shaun, and Rebecca arrive at Monteriggioni, where they set up a safe house in the Villa Auditore's sanctuary. Desmond re-enters the Animus 2.0 to discover the location of the Apple of Eden obtained by Ezio, hoping to use the artifact to defeat the Templars and stop the cataclysm Minerva warned Desmond about. Through Ezio's memories, Desmond and the others learn the Apple is hidden under the Colosseum and head there to retrieve it. Desmond takes the Apple, and through it, Juno, another First Civilization member, takes control of his body and forces him to stab Lucy, claiming that she would have betrayed him if he allowed her to accompany him any further. Desmond then falls into a coma, and is placed back into the Animus by two unknown Assassins in a bid to preserve his consciousness.

In Assassin's Creed: Revelations, Desmond awakens within the Black Room, a "safe mode" area for the Animus. In the Black Room's "Animus Island", he meets the digital construct of Subject 16, Clay Kaczmarek, who explains that Desmond must find a memory that links him with Altaïr and Ezio so he can reintegrate his shattered subconscious and awaken from his coma. While in this state, Desmond can hear conversations between Shaun, Rebecca, and his father, William Miles. When the Animus begins to delete Animus Island, Clay sacrifices himself to prevent Desmond's consciousness from being deleted, but not before transferring his own genetic memories onto Desmond. Afterwards, Desmond is approached by Jupiter, a member of the First Civilization, who tells him where to find the Grand Temple that contains most of the data collected by his race over the years, so that he may prevent the cataclysmic solar flare set to occur in a few weeks. After awakening from his coma, Desmond sees Shaun, Rebecca, and William sitting around him. When his father asks if he is alright, Desmond simply states that he knows what they have to do.[29]

While in the Black Room, there are five sequences where Desmond talks about his life prior to being captured by Abstergo. In Desmond Sequence 1, he expresses regret for running away from "The Farm", where he grew up in secrecy among other Assassins, and also wishes that he could apologize to his parents. In Desmond Sequences 2 and 3, Desmond explains his early life on the Farm and the training he went through. He also describes his escape, which happened at the age of 16. He ran away into the Black Hills, before running into girls from Illinois who drove him to Chicago. After this, he moved to New York City. During Desmond Sequence 4, Desmond talks of his life in New York, and the job he got at a high-end bar. In the last sequence, Desmond Sequence 5, Desmond describes how Abstergo eventually found him in 2012 and how much he regretted not taking his parents' warnings and training more seriously, and finally accepts his role as an Assassin.

In The Lost Archive DLC, Desmond, during his time in the Animus, unwillingly experiences Clay's memories prior to his death. He learns that Clay used to be an Assassin, and that he was tasked with infiltrating Abstergo to learn what Warren Vidic hoped to achieve by accessing the memories of different Assassins. Lucy, who had infiltrated Abstergo years prior, was to safely extract Clay after his mission was complete. However, Clay eventually discovered that Lucy had secretly betrayed the Assassins and joined the Templar cause, and that Vidic ordered her to take Desmond to a place where he would feel safe, so that she could analyze the memories of his ancestors and find Ezio's Apple of Eden; Abstergo would then steal the Apple from the Assassins and use it control the entire planet through a satellite. When Lucy discovered that Clay had learned about her treachery, she imprisoned him at the Abstergo facility, where Clay was eventually driven to insanity and took his own life.

In Assassin's Creed III, Desmond, who is noticeably thinner and frail after a long time in Animus, arrives at the Grand Temple of the First Civilization, located in a cave system in New York, and accesses it using Ezio's Apple of Eden. With the help of his father and friends, Desmond relives the memories of his ancestors Haytham Kenway (1725–1781; Kingdom of Great Britain) and Ratonhnhaké:ton / Connor (1756–unknown; Colonial America) using the new Animus 3.0,[3] hoping to find the Key to the Temple's Central Vault. Occasionally, Desmond leaves the Animus to explore the Temple and speak with Juno, who tells him more of her race's history, as well as to retrieve "batteries", which are also required to access the Central Vault. While searching for the batteries in Manhattan and São Paulo, Brazil, Desmond is hunted by Daniel Cross, a Templar agent dispatched by Abstergo who was responsible for the purge of most of the Assassin Brotherhood a decade prior. After William is captured while trying to recover the last battery, Desmond storms Abstergo's headquarters in Rome, kills Cross and Warren Vidic, and rescues his father.

After finding the Key, Desmond and his allies enter the Central Vault, where Minerva and Juno appear to speak with Desmond. Minerva warns Desmond that if he touches the pedestal in the center of the room, he will be killed and Juno will be released, allowing her to conquer humanity, but the world will be saved. Juno shows Desmond how his divinity among the survivors of the catastrophe would end with the world going through another cycle of political and religious war. Desmond ultimately decides to use the device and save the world, believing it has a better chance of fighting Juno. While Shaun, Rebecca, and William exit the Temple, Desmond touches the pedestal and releases Juno, dying in the process.

According to lead designer Steve Masters, Desmond's story ends in Assassins Creed III: "What we're trying to do is bring some finality to Desmond's story. To actually wrap up what you've opened and experienced with him." The creative director of the series, Jean Guesdon, said that Desmond is an important character in the Assassin's Creed series, and would be playing an important role in the sequel.[30]

Despite his physical death, Desmond is still a powerful asset for the Templars and Assassins in Assassin's Creed IV: Black Flag. Shortly after Desmond's death, a sample recovery team from Abstergo is sent to collect his body and samples for the new Sample 17. Desmond's DNA is stored in Abstergo Entertainment's servers, where a crew of analysts is tasked with reliving his copied genetic memories and learning about his ancestors. One of them, the player character, is tasked with reliving the memories of Edward Kenway (1693–1735; Wales), a pirate who lived during the Golden Age of Piracy and eventual member of the Assassin Brotherhood, as well as the father of Haytham Kenway and grandfather of Connor. While this is ostensibly to gather data for an Animus-powered interactive feature film starring Edward, in reality Abstergo seeks to find the Observatory, a First Civilization structure hosting an advanced tracking device and several vials of First Civilization's blood samples.

The analyst steals and sends back to the Assassins several recordings left by Desmond detailing his initial doubts of leaving the Farm, his acceptance of the role he had been chosen to play, and his love for his parents. Because Abstergo can now collect anyone's genetic memories without having to use blood-related analysts, Desmond's body gives Abstergo full knowledge about his family life.

In 2015, during the events of Assassin's Creed Syndicate, a boy named Elijah is brought by his mother to an Abstergo clinic in New York City. Abstergo analysts discover that the boy shares exactly the same patrilineal lineage of Desmond Miles, indicating that he may have been unknowingly conceived by Desmond a few years after his escape from the Farm. On top of that, it is also revealed that the boy is a Sage, a modern-day reincarnation of a First Civilization member. An Abstergo researcher proposes to kidnap the boy and conduct vivisection on him. However, another researcher, Isabelle Ardant, opposes the idea, claiming that it would be better to abduct the boy when he is older and place him in the Animus for 50 years so that Abstergo can study his lineage.

In Assassin's Creed Valhalla, it is revealed that, while Desmond's phyisical form was killed when he activated the First Civilization towers in 2012 to save the Earth, his mind was transported into a computer simulation created by the First Civilization known as "The Grey". During his time there, he forgot his original identiy and was transformed into a being of light called The Reader. In 2020, the Assassin Layla Hassan enteres the Grey via a supercomputer from a First Civilization temple in Norway in an attempt to slow the magnetism of the global aurora borealis device. Here, Layla meets the Reader and shows him more possibilities and calculations based on timelines he had not explored. The Reader then tells Layla she has a minute to live as the radiation from the chamber is killing her physical body. Layla decides to stay in the Grey with the Reader and explore more timelines.