The design philosophy behind Mirage—the first game to be developed primarily by Ubisoft Bordeaux, previously just a support studio—was to return to the series' roots by focusing on stealth, parkour, and assassinations over the role-playing elements featured heavily in recent installments.

Baghdad is much smaller than the worlds of recent Assassin's Creed titles, being closer in size to Unity's and Revelations' depictions of Paris and Constantinople, respectively.

[7] Furthermore, moving and running animations have been refined to improve mobility and fluidity, with the development team taking inspiration from "samurai, ninja, and even Jedi to a certain point".

[8] Assassin's Creed Mirage is set in Baghdad during the Islamic Golden Age, primarily during the Anarchy at Samarra, which was a period of extreme internal instability during the reign of the Abbasid Caliphate.

Taking place a decade before the events of Assassin's Creed Valhalla, the game explores the backstory of Basim Ibn Ishaq (voiced by Lee Majdoub), depicting his transition from street thief to fully-fledged Hidden One, under the tutelage of his mentor, Roshan bint-La'Ahad (Shohreh Aghdashloo).

In retaliation for the Caliph's murder, the guards begin slaughtering all thieves in Anbar, including many of Basim's friends, and he angrily blames Nehal before parting ways.

When their Mentor, Rayhan, learns of the Order's rapidly expanding influence in Baghdad, he decides to send a contingent of Hidden Ones to the city to investigate, led by Basim and Roshan.

Eventually, Basim confronts the Order's leader, al-Mutawakkil's former concubine Qabiha in the Abbasid harem, who claims that the answers he seeks lie in an Isu temple underneath Alamut.

Basim rescues many captured Hidden Ones and rallies them to fight off the attack while he heads to the temple after convincing Rayhan that the power held within could be used to defeat the Order for good.

Prior to its announcement at Ubisoft Forward on 10 September 2022, details about Mirage leaked–under the codename Rift–when it was revealed that the game started out as an expansion pack for Assassin's Creed Valhalla before being turned into a standalone release.

[23] The creation of the database involved four academic experts in Islamic art,[24] and was supported with grants from the UK's Economic and Social Research Council and the charity Barakat Trust.

Frontman Ryan Tedder said, "Having toured extensively in the Middle East, I wanted to capture the spirit of that region and reflect the location of the game sonically as much as possible.

[35] A second free update, released on 20 February 2024, added a permadeath mode called "Full Synchronization", which upon completion offers players various rewards, including new outfits and dyes.

[59] GamesRadar+ complimented the dense nature of Baghdad in comparison to recent entries, saying: "Markets bustle with shoppers and traders speaking multiple languages, streets see people meander in clusters".

[47] While enjoying the focus on stealth and calling the game a "back-to-basics approach" a successful first step in returning to the stealthy style, IGN felt the character of Basim was dull, writing, "He's a pretty milquetoast, golden retriever of a man, largely agreeable and affable when it comes to his interpersonal relationships.

"[45] GameSpot praised the social stealth, world design, and investigations, but criticized the storyline's reliance on previous entries and uninteresting supporting characters.

[46] In Japan, the PlayStation 5 version of Assassin's Creed Mirage sold 20,407 physical units in its first week of release, making it the third best-selling retail game in the country.