Mass Effect is a science fiction video game series created by Casey Hudson. The series shows a future far away where humans and many alien species have settled in different parts of the galaxy using technology left behind by highly advanced civilizations.

The series began with a set of video games made by BioWare and first released by Microsoft Game Studios for the first two games and their expansions. Later, the series was managed by Electronic Arts after it bought BioWare. Each game is a third-person shooter where players make choices that affect the story. The first three games form a trilogy where the player controls Commander Shepard, a leader trying to protect the Milky Way galaxy from ancient, sleeping machines called the Reapers. The first game, Mass Effect (2007), follows Shepard’s investigation into Saren Arterius, one of the Reapers’ agents. Mass Effect 2 (2010) takes place two years later and shows Shepard fighting the Collectors, an alien group that captures human colonies to help the Reapers return. The trilogy’s final game, Mass Effect 3 (2012), describes a war between the Reapers and the galaxy’s other civilizations. A fourth game, Mass Effect: Andromeda (2017), introduced new settings and characters, and a fifth game is currently being developed.

The first three games were very successful and received high praise from critics. Reviewers liked the game’s story, characters, voice acting, world creation, and the way choices affect the game. The ending of Mass Effect 3 was criticized for being unsatisfying, so Electronic Arts added extra scenes to improve it. Mass Effect: Andromeda received mixed reviews. Some praised its graphics and battles, but others pointed out technical problems and issues with the story.

The series has sparked discussions about how it portrays same-sex relationships and people from different sexual backgrounds. It also introduced the dialogue wheel, a feature that lets players choose how characters speak during the game by selecting from preset options. This feature is now used in many other role-playing games. The success of the video games led to other versions of the story, including books, comics, and an animated movie.

Setting

The Mass Effect original trilogy takes place in the Milky Way near the end of the 22nd century. In 2148, humans found an alien base on Mars and learned that Charon is an alien structure called a "mass relay." This structure allows faster-than-light travel to other mass relays across the galaxy. These discoveries greatly improved the speed of human technological progress.

Humans met many other alien species that travel in space, some much more advanced than humans. The first meeting led to the First Contact War, but the Council, a group that rules the galaxy, helped stop the war and welcomed humans. Important species humans met include the asari, a species of beings that look like human women; the salarians, a species that lives in water and on land, with high intelligence and fast metabolism; and the turians, a race of bird-like humanoids that fought humans in the First Contact War.

The Citadel is the main place where the Council makes decisions. It is also a large space station, like the mass relays, believed to have been built by the Protheans, a race that was the ancestor of all species but disappeared long ago. Over the next few decades, humans gained new technology, allowing them to settle new planets. They also joined the Citadel Security (C-Sec) forces, a respected role that other species had wanted for a long time, causing some to feel upset. Many conflicts between species were still happening when the first game began.

The first three games follow Commander Shepard, a special forces soldier in Earth's Systems Alliance Navy. After an Earth colony finds a new Prothean artifact, it is attacked by an unknown ship. The Council names Shepard the first human SPECTRE, an elite agent with special authority, to investigate.

Shepard sees the artifact and has a vision of war and death across the galaxy. Shepard later learns the strange ship is one of many artificial lifeforms called Reapers. Every 50,000 years, the Reapers destroy all advanced life in the Milky Way to allow younger species to grow and avoid endless war, a plan left by the Protheans. The Reapers’ return in this cycle is being controlled by groups like Cerberus, a human-focused terrorist group led by the Illusive Man, who believe they can use the Reapers to help humans. Shepard and allies find the Citadel is key to stopping the Reapers and deciding the galaxy’s future.

The fourth game takes place in the Heleus Cluster of the Andromeda galaxy, 634 years after the first three games. During the events of the first three games, the Milky Way species sent ships to Andromeda to build the Nexus, a space station and future colonies. After over 600 years of travel in frozen sleep, they arrive to find the Heleus Cluster in conflict between two native species: the Kett, a violent race that tries to copy traits of other species through a process called "exaltation"; and the Angara, a highly emotional humanoid species whose civilization was nearly destroyed by the Kett.

The Heleus Cluster also has ruins from the Jardaan, an advanced race that used powerful technology to make planets habitable. The Jardaan left the cluster three centuries before the Milky Way species arrived after a long battle with an unknown enemy. A weapon of mass destruction was used on a Jardaan space station, causing a destructive energy event called the Scourge, which damaged the Jardaan’s terraforming systems. After the Jardaan left, the Angara, created by the Jardaan, began building their own civilization but were attacked by the Kett.

Now, the arrival of Milky Way species makes it the job of Pathfinder Ryder (like Shepard, customizable by the player) and their allies to stop broken terraforming systems, deal with attacks from the Kett and Angara, and make planets suitable for colonization.

Gameplay

The Mass Effect games are action role-playing games. Players create their own main character (Shepard in the first three games and Ryder in Mass Effect: Andromeda) by choosing their appearance, background, and one of six character classes. Each class focuses on combat, technology, or special abilities called "biotic" skills, similar to powers seen in other games. As the character gains experience by completing missions, they can improve their abilities through a system called a skill tree.

Each game follows a main story with choices that lead to different paths and side missions. Players use their ship to travel through space using mass relays to explore planets and complete objectives. During exploration, players can bring up to two crew members who act on their own but can be given specific tasks. Missions often involve searching for items, talking to characters, and recovering important objects. Combat is shown from a third-person view, with players using weapons, special powers, and the environment to defeat enemies.

There are six types of weapons: assault rifles, grenades, sniper rifles, shotguns, pistols, and later, heavy weapons like grenade launchers and flamethrowers. These weapons can be folded for storage, allowing players to carry multiple weapons at once. Melee weapons include fists, the butt of a gun, or a special dagger called an Omni-blade in later games.

Players interact with other characters through dialogue choices, which are shown on a circular menu called a Dialogue Wheel. These choices affect the story and the character’s morality, such as being a Paragon (kind and noble) or Renegade (ruthless and bold). In later games, these choices also influenced how the story progressed and which allies the player could gain. In Andromeda, the Paragon/Renegade system was replaced with a new system based on four attitudes: emotional, logical, casual, and professional.

Side missions include building relationships with crewmates, including romantic options with characters of different genders and species. Players can improve these relationships through dialogue, giving gifts, or completing specific tasks. Romance options led to scenes showing the start of a relationship but did not include inappropriate content. These features caused some controversy when the first game was released, as some critics commented on the game’s portrayal of relationships.

Games

Mass Effect (2007), the first game in the series, was created for the Xbox 360 but later made available for Windows by Demiurge Studios in 2008 and for PlayStation 3 by Edge of Reality in 2012. The game follows Commander Shepard, the protagonist, as they work to stop Saren Arterius, a rogue Spectre, from leading an army of sentient machines called the geth to conquer the galaxy. While chasing Saren, Shepard builds relationships with other characters, especially their squad members, and learns about a greater threat: the Reapers. Saren has been controlled by Sovereign, a Reaper vanguard, and sent to begin the Reapers’ cycle of destroying advanced life in the galaxy every 50,000 years.

Two downloadable content packs, Bring Down The Sky and Pinnacle Station, were released in 2008 and 2009.

Mass Effect 2, the second main game, was released on January 26, 2010, in North America and January 29, 2010, in Europe for Windows and Xbox 360. Before its release, little was known about the game, except that BioWare’s Project Director, Casey Hudson, said players should keep their save files from Mass Effect because choices made in the first game would affect the sequel. The story takes place two years after Mass Effect. Human colonies are being attacked, and their people are disappearing. Shepard must work with Cerberus, a pro-Human group, to find the cause. Evidence points to the Collectors, an advanced race of insect-like beings who are working for the Reapers. Shepard leads a team on a dangerous mission to stop the Collectors. Mass Effect 2 received strong praise for its characters, story, voice acting, and gameplay, with many calling it a major improvement over the first game. A PlayStation 3 version was released on January 18, 2011.

Seven episodic expansions were released as downloadable content, including Normandy Crash Site, Zaeed – The Price of Revenge, Firewalker, Kasumi – Stolen Memory, Overlord, and Lair of the Shadow Broker in 2010, followed by Arrival in 2011.

Mass Effect 3, the third game in the trilogy, was released on March 6, 2012. Casey Hudson said it would be easier to develop because the story would not need to connect to a future game. However, choices from the first two games still influenced Mass Effect 3 to keep the series’ story consistent. In this game, the Reapers return and attack Earth. Shepard must escape Earth, rally other advanced species, and stop the Reapers to break a cycle of destruction that has repeated for millions of years. The first trailer was shown on December 11, 2010. This game was released for Xbox 360 and PlayStation 3 on the same date and did not involve Microsoft Game Studios.

Four story-focused expansions were released as downloadable content in 2012 and 2013: From Ashes, Leviathan, Omega, and Citadel. Five free DLC packs for the multiplayer mode were also released in 2012 and 2013, adding new characters, weapons, maps, and enemy factions.

Mass Effect: Andromeda, the first game in a new series and the fourth main game overall, was announced at E3 2015 and released on March 21, 2017. It uses DICE’s Frostbite 3 engine and was available for PlayStation 4, Windows, and Xbox One. This game introduced an open-world environment and features players as Sara or Scott Ryder, Pathfinders exploring the Andromeda Galaxy. Unlike previous games, Andromeda did not have single-player expansions, but its multiplayer mode received updates in 2017 with new content.

In 2020, BioWare announced a new Mass Effect game was in development. A trailer released on December 11, 2020, hinted at a sequel to the original trilogy and featured Liara T’Soni, a character from the first games. The new game will use the Epic Games Unreal Engine, which was also used in the original trilogy, instead of the Frostbite engine used in Andromeda.

In November 2022, BioWare announced several lead developers, including some from the original trilogy. Concept art and an encrypted audio file featuring Liara T’Soni were also shared. In November 2023, a teaser trailer and poster for the new game were revealed, along with details about returning developers.

Mass Effect Galaxy is a game set between Mass Effect and Mass Effect 2, available only on iOS. It follows Jacob Taylor and Miranda Lawson, characters who appear in Mass Effect 2. The story involves Jacob defending a ship attacked by batarian raiders and later helping with an Alliance mission. The game was removed from the iOS App Store.

Mass Effect Infiltrator is a third-person shooter available on Android, BlackBerry 10, iOS, and Windows Phone 8. It follows Randall Ezno, a Cerberus agent who turns against the group. Players earn rewards for uncovering Cerberus’ crimes, which affect the Galaxy at War system in Mass Effect 3. The game was later removed from all app stores.

Mass Effect: Datapad was a free iOS app that let players check the status of the galaxy map in Mass Effect 3 and receive messages from characters. It included information about the game’s universe and mini-games linked to the Galaxy at War system. The app was removed from the iOS App Store and Google Play Store on June 5, 2013.

Other media

Original trilogy tie-in novels published by Del Rey Books:
Mass Effect: Andromeda tie-in novels published by Titan Books:
All published by Dark Horse Comics:

On November 23, 2021, Deadline Hollywood reported that discussions were happening to create a Mass Effect series for Amazon Prime Video. In November 2024, Amazon announced the series was being developed by Karim Zreik through Cedar Tree Productions, along with Ari Arad and Michael Gamble from Electronic Arts. Daniel Casey is writing and producing the series. On June 6, 2025, Doug Jung was hired as the showrunner. In November 2025, it was shared that the show would tell a new story set in the Mass Effect timeline, taking place after the original trilogy.

Two series of action figures were released by DC Direct and Big Fish Toys for Mass Effect 2 and Mass Effect 3. The first series included figures of Commander Shepard, Grunt, Tali, and Thane. The second series included Garrus, Legion, Miranda, and Mordin. Each figure includes accessories that match the game. They are sold in game and hobby shops and online stores. Figures from Mass Effect 3 come with extra downloadable content, which is unique for each character.

Development and history

Mass Effect began as a project idea in 2003, named SFX, proposed by BioWare project director Casey Hudson to the company’s co-founders, Ray Muzyka and Greg Zeschuk. Hudson wanted BioWare to create its own science fiction intellectual property, similar in size and detail to the Star Wars universe. On October 11, 2007, just before the original Mass Effect game was released for the Xbox 360 in November 2007, it was announced that EA purchased VG Holding Corp., a partnership between BioWare and Pandemic Studios formed in November 2005. As part of this deal, EA acquired the Mass Effect intellectual property, and BioWare continued to develop the series.

The technology in the Mass Effect series is based on the idea of dark energy, a type of energy thought to drive the universe’s expansion and a possible tool for faster-than-light (FTL) travel. In the game’s fictional world, applying a strong electric current to Element Zero, or "eezo," through dark energy creates "mass effect" fields. A positive current increases the mass of objects, helping to generate artificial gravity, while a negative current decreases mass, making FTL travel more efficient. The stronger the current, the greater the effect. Other real-world scientific ideas explored in the series include 3D printing for the omni-tool concept, hard light technology, and hypervelocity weaponry. Hudson believed that real scientific discoveries often inspire creative ideas, stating that "reality will continue to be stranger than fiction," which supports the series’ creative choices.

Morality in the first three main games is measured using "Paragon" and "Renegade" points, a system inspired by the light and dark side of the Force from BioWare’s earlier game, Star Wars: Knights of the Old Republic. A spin-off game titled Mass Effect: Corsair, designed for the Nintendo DS and based on gameplay from Star Control, was planned in 2008. It would have followed a space pirate character from a first-person perspective. However, the project was canceled due to the high cost of Nintendo DS cartridges and low sales expectations. The team instead focused on developing Mass Effect 2. For the 2017 game Mass Effect: Andromeda, the Paragon and Renegade system was removed entirely.

In 2007, BioWare applied for a patent for the Dialogue Wheel, a "graphical interface for interactive dialog." The patent was granted to EA International Studio and Publishing Ltd. in 2011.

The Mass Effect universe draws inspiration from many science fiction works, including Star Trek, Blade Runner, Firefly, and Battlestar Galactica. Other influences include the films Alien, Starship Troopers, Dune, and Final Fantasy: The Spirits Within. Video games like Deus Ex, Halo, and Starflight also shaped the series’ gameplay.

Greek mythology appears in the series through names like the planet Elysium and the group Cerberus, as well as story themes, such as the Protheans’ technological legacy.

The music of the series is similar to the vintage synthesizer score of Blade Runner, creating a mood that reflects the mystery and danger of space. Jack Wall, the composer for the first two games, blended electronic sounds from the 1970s and 1980s with organic elements. Later games used more cinematic, orchestral styles, while still including some of Wall’s earlier work.

Reception

The original Mass Effect trilogy has received very high praise from critics on all platforms, according to Metacritic. Each of the three games received many nominations and several year-end awards from video game publications and major award events. The first two games in the series are often considered among the best games ever made. Mass Effect 2, in particular, is the most highly praised game in the series and won many "game of the year" awards after its release. It received more than 70 perfect scores from reviewers. In 2013, IGN ranked the Mass Effect Trilogy as the best Xbox 360 game(s) out of 25, and the 7th best PS3 game(s) out of 25.

The fourth game, Mass Effect: Andromeda, received less positive reviews from critics. Most critics agreed that it was not as good as the earlier games in the series, though some praised its improved combat system.

The Mass Effect franchise has been commercially successful. The first game sold more than one million copies worldwide in under three weeks after its release. Sales reached 1.6 million copies by January 2008, six weeks after launch. Its sequel, Mass Effect 2, shipped over two million copies to retailers in its first week. The game sold over 500,000 copies during its release month, even though it launched near the end of the month. Before the third game was released, the series had sold a total of 7 million copies worldwide. Mass Effect 3 was the most successful game in the series: it sold over 800,000 copies in its first 24 hours, and its first month of sales was twice that of its predecessor. It sold over 900,000 copies on Xbox 360, selling four times as many copies on Xbox 360 compared to PlayStation 3, and earned over $200 million in revenue. By April 2012, it had sold more than twice as many copies as Mass Effect 2 in their respective launch months, with lifetime sales exceeding six million copies. By July 5, 2014, the entire series had sold 14 million units worldwide.

Mass Effect: Andromeda continued the series’ sales success. By May 2017, an analyst reported that at least 2.5 million retail copies of Mass Effect: Andromeda had been shipped, generating $110 million in revenue. Additionally, $53 million in net sales from digital and special editions of Andromeda were recorded in March 2017, though these sales were reported later.

Legacy and cultural impact

Tauriq Moosa from The Guardian praised the Mass Effect series as one of the best science fiction stories ever created. He said the series' main theme—"aspiration and connection in the face of an indifferent universe"—was as thoughtful as Star Trek, as hopeful as Asimov, and as dramatic as Battlestar Galactica. Jessi Sampson from PCGamesN agreed, calling Mass Effect a "mix of ideas" from important science fiction works. She noted that the first game and its creators influenced the video game industry and left a lasting legacy. Jonathan Wood from Wired said the first Mass Effect set a high standard for storytelling in video games that few others matched. Benjamin Bullard from Syfy pointed out that the first game was released when science fiction games often focused on conflict and violence between aliens and humans. Over time, the Mass Effect franchise grew from a small role-playing game into a major, high-quality game series.

In 2010, GamesRadar called Mass Effect the best new game series of its generation. It praised the game's detailed galaxy setting, which felt like a long-established series and showed how well video games could tell stories. Colin Moriarty said the Mass Effect series was one of the most important game series of its generation. Kyle Munkittrick from Gizmodo argued that Mass Effect was the most significant science fiction universe of its time. Patrick Carlson from PC Gamer called Mass Effect one of the greatest science fiction stories across all forms of media. He credited the series for combining classic space adventure elements with a role-playing game format that allowed players to face both fun and serious challenges. Cian Maher from TheGamer said the series' detailed written entries in the game's codex helped create one of the most interesting universes in video game history.

N7 Day is a special day celebrated on November 7 each year by BioWare, Electronic Arts, and fans of Mass Effect. It started in 2012 as a marketing effort by BioWare to honor the Mass Effect series. "N7" refers to Commander Shepard's in-game military code. The "N" stands for special forces, and the "7" represents Shepard's high rank in the game's universe.

The Mass Effect series has inspired many fan-made works. However, the series has also faced several controversies. A scene in the first Mass Effect game, which showed partial nudity and sexual activity, was criticized by some media outlets as inappropriate. This led to government attention and a temporary ban of the game in Singapore. The controversy caused BioWare to remove planned same-sex romantic storylines for characters like Jacob Taylor and Jack in the next game.

Mass Effect 3 received praise from critics but also faced backlash over its ending. Many players were unhappy with the conclusion and organized online campaigns to demand a better ending. The U.S. Federal Trade Commission and the British Advertising Standards Authority received complaints that BioWare misled players about the game's ending. BioWare later released an "extended cut" update to expand on the ending but not change it. The company also faced criticism for how it handled the release of the Mass Effect 3: From Ashes DLC and for potential conflicts of interest involving video game personality Jessica Chobot.

Other controversies include claims that the series' violent content was linked to the Sandy Hook Elementary School shooter, a claim later proven false. A video using assets from Mass Effect 2 was used in a 2016 campaign for Donald Trump, but it was removed after copyright issues. The series has also faced criticism over how it portrays women and sexual minorities.