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For other articles titled "KOS-MOS", see KOS-MOS (disambiguation).
KOS-MOS Art XS1.png
KOS-MOS ver. 1 from Episode I
Species Android
Blade (XC2)
Gender Female
Age 2
3 (Episode III)
18 (Appearance)
Height 167 cm (Ver. 1)
Weight 92 kg (Ver. 1)
Designer Kunihiko Tanaka (XS1, XC2)
Japanese VA Mariko Suzuki
English VA Bridget Hoffman (XS1, XS3)
Colleen O'Shaughnessey (XS2)
Luci Christian (The Animation)
Caitlin Thorburn (XC2)
Appearances Xenosaga Episode I
Xenosaga Episode II
Xenosaga Episode III
Xenosaga Freaks
Xenosaga I & II
Xenosaga II to III: A Missing Year
Xenosaga Outer File
Xenosaga: The Animation
Xenoblade Chronicles 2
Namco X Capcom
Project X Zone
Project X Zone 2
Venus & Braves
Super Robot Taisen OG Saga: Endless Frontier
Super Robot Wars OG Saga: Endless Frontier Exceed
Tales of the Rays

KOS-MOS is the central character of the Xenosaga series. She is an anti-Gnosis battle android developed by Vector Industries' First R&D Division and the magnum opus of the KOS-MOS project.

Appearance and personality[edit]

In all her versions, KOS-MOS resembles a young woman with long blue hair and red eyes. As the Archetype, KOS-MOS wears a grayish bodysuit with fading yellow accents, a Hilbert emission helmet and her eyes are obscured by a visor. After the Archetype's destruction, she is rebuilt as KOS-MOS ver. 1; she wears the Hilbert emission visor above her head, a greyish blue skirted leotard and white high heel boots. After being upgraded to KOS-MOS ver. 2 by Vector's Second R&D Division, the Hilbert emission device is embedded in her forehead after losing the original after the Elsa descends into Second Miltia and now wears a full blue bodysuit with blue anti-G gel all over her body, with the Swimsuit skill equipped, KOS-MOS wears a grey one-piece swimsuit with sleeves. As KOS-MOS ver. 3, she once again wears the Hilbert emission visor above her head and now wears a black and white bodysuit with her lower breasts exposed. After being heavily damaged by T-elos, KOS-MOS ver. 4 wears a small white dress with straps attached to her boots; unlike the other version of KOS-MOS, this one is not developed by Vector Industries, but rather the Professor, her swimsuit consists of a white bikini with purple trims.

As an android, KOS-MOS acts in a logical decision. She is also programmed to unconditionally protect her creator, Shion. KOS-MOS is equipped with a "Simulated Personality OS" to better communicate with humans. A predetermined set of emotions were coded into KOS-MOS and will only exabit it such as sadness when necessary.

Story arc[edit]


KOS-MOS is a female anti-gnosis battle android developed by Vector Industries. In contrast to current Realian technology, she is made up entirely of mechanical parts. She was created by Kevin Winnicot and Shion Uzuki. As her creator, KOS-MOS unconditionally protects Shion. KOS-MOS stands for Kosmos Obey Strategic Multiple Operation Systems. Her serial number is 00-00-00-00-1. She has the ability to activate the Hilbert Effect, which will cause gnosis to be brought into the same reality as the humans they interact with.

Prior to the events of the game, Kevin arranged to provide access to Cherenkov and soldiers of the U-TIC Organization to enter the facility where KOS-MOS was being developed. While Cherenkov hoped to seize KOS-MOS, she instead went out of control, killing not only the U-TIC Soldiers but her developers as well, Kevin included. This version of KOS-MOS was eventually stopped by Shion by blasting its head off with hand cannon, destroying it, with only her and Cherenkov as the survivors.

Episode I[edit]

KOS-MOS begins the game still in development, with Shion traveling into the KOS-MOS Simulator to test her abilities. She was stationed on the Woglinde to help defend it in the event the Gnosis arrived. However Shion and the development team have no actual field data on her, as she has solely been used in simulations. When the Gnosis attack the Woglinde, KOS-MOS awakens on her own. She is able to ensure the escape of the Vector employees and make her way to Shion along with Allen. As the two head towards the escape pods they are accompanied by the soldier Virgil. When Virgil stands in her line of fire, KOS-MOS kills him, not wanting the reduction in offensive capability that avoiding him would cause. This horrifies Shion greatly. KOS-MOS and Shion are able to defeat additional Gnosis in their way and Shion and Allen make their way into an escape pod to depart the Woglinde. As they depart KOS-MOS confirms that the Woglinde didn't capture the original Zohar, but rather an emulator. This information appears to have been transmitted directly to the Red Testament and Vector CEO Wilhelm.

The passenger ship Elsa soon comes across KOS-MOS. She requests they gate jump to Second Miltia and bring her there, threatening to kill them all if they don't do what she says. The Elsa crew reluctantly let her inside. When the Elsa finds Shion's escape pod, KOS-MOS wants to leave it for the Federation rescue vessels to pick up. KOS-MOS relents after Shion threatens to kill herself and Allen, and chaos appears aboard the bridge and requests they recover them. Shion continues to be surprised by KOS-MOS acting on her own as well as following a mission that Shion is not aware of all the details of. KOS-MOS is permitted usage of the ship's generator to replenish her energy reserves. While she rests she is visited by chaos, who asks where the real her exists. She is also visited by Cherenkov, who is frightened by her and pulls out a gun before Shion shows up.

Shion demands and is permitted from her boss the ability to remain by KOS-MOS's side, so she can determine why she is acting on her own. While on board the Elsa KOS-MOS helps with the dishes and fighting off U-TIC soldiers when Ziggy and MOMO board the ship. When the Elsa comes across the Cathedral Ship, KOS-MOS activates the Hilbert Effect, but the Elsa and all its crew members are nonetheless pulled into it. KOS-MOS picks up a signal similar to that of the Zohar Emulator and the party makes their way there. After they find the Emulator and kill Cherenkov, who has turned into a Gnosis, the Cathedral Ship starts to fade away, but there is still a massive amount of Gnosis in the area. On her own, KOS-MOS travels up the Elsa's elevator and her eyes turned blue, uttering that feeling pain would make her complete. She then flies to back of the ship and uses X-BUSTER and wipes out all the remaining Gnosis with its remains being absorbed into KOS-MOS. Her eyes then turn back to red.

When the U-TIC Organization frames the Kukai Foundation for the destruction of the Woglinde, the party is able to prove their innocence by diving into the Encaphalon and recovering KOS-MOS' database. Before departing the Encephalon, Shion has a vision of KOS-MOS and the planet Miltia firing at each other, causing a large explosion. They also find KOS-MOS tied to a crucifix-shaped stone. When the Gnosis attack the Kukai Foundation shortly afterwards, KOS-MOS again activates the Hilbert Effect to assist in defeating them. Using a phase transfer cannon set up for KOS-MOS by Vector, she fires upon the invisible base summoning the Gnosis, the Song of Nephilim, revealing it.

When Albedo tries to access the Y-Data, KOS-MOS appears, protecting it, and saying she does not exist for his pleasure. KOS-MOS heads into the Song of Nephilim along with the party, and then Proto Merkabah. As Proto Merkabah starts descending into the atmosphere of Second Miltia, KOS-MOS stays behind to detach the base's sub components. She is able to do so and make it back to the Elsa as it departs, with Ziggy grabbing a hold of her as she jumps right near the ship. As the Elsa descends towards Second Miltia is starts burning up. KOS-MOS jumps off the ship, in front of it, and activates her energy shield in order to cool its descent. During that time, KOS-MOS's eyes turned blue again. She is last seen standing in front of the ship

Episode II[edit]

At the start of the game, KOS-MOS is brought to Vector's Second R&D Division on Second Miltia by Shion and Allen. There, the supervisor shows them a diagram of the KOS-MOS Tertiary Weapon System being developed for her. Shion agrees to transfer KOS-MOS over to them. As they leave, Shion tells Allen to keep his eye on KOS-MOS. When the party dives into the Subconscious Domain, Allen provides KOS-MOS' data so she can accompany them.

When Shion heads towards Old Miltia in the Dinah, KOS-MOS awakens on her own while at the Second R&D Division and gets onto a craft that she uses to head into space, claiming Shion is calling her. She soon catches up with the Dinah and combines the craft with it, being able to fight off the enemy forces with it. During this her eyes temporarily change to blue again. KOS-MOS accompanies Shion and the others as they make their way through the Ormus Stronghold, then down to Old Miltia and into Labyrinthos. There she destroys the Zohar Control System once it starts to link with U-DO, killing Cecily and Cathe who are connected to the system. At the Ω System, when Albedo starts linking with U-DO, KOS-MOS claims she can hold things off for three minutes and recommends Shion and the others escape. She is able to escape along with the others on the Elsa.

A Missing Year[edit]

When the Gnosis raid the S.O.C.E. lab due to the Gnosis terrorism, Shion and KOS-MOS made their way to evacuate as many survivors as they can. However a Sciantia agent, Doctus kidnaps Almadel and damages KOS-MOS. After the incident KOS-MOS is upgraded into V3 by Vector Industries. KOS-MOS later saves Shion from Almadel who is undergoing the Whitening process. in Ares Nova, an area of S-division within the U.M.N., sealed by Vector. Despite KOS-MOS and Jin Uzuki's efforts, Almadel dies. After her death, KOS-MOS helps Shion up.

Episode III[edit]

At the start of the game, Vector scrapped the KOS-MOS project in favor of the T-Weapon Program that resulted in T-elos. KOS-MOS is seen being tested on Omega Res Novae in which she is badly damaged. Ultimately, it was revealed that the KOS-MOS project is scrapped by Roth Mantel, being replaced by T-elos and was ordered for her to be disposed. KOS-MOS is later found in the landfill of the CAT Testing Ground by the party who is then promptly rebooted by Shion and Allen. KOS-MOS accompanies the party to Rennes-le-Château to rescue the stranded Elsa, by breaking the its hypersphere. At Mary Magdalene's tomb, the party is ambushed by T-elos and is heavily damaged. As she lays defeated, her eyes briefly turn blue again after reacting to Shion's pendant.

When KOS-MOS's body is examined by Shion, Allen, the Professor and Scott, they initially concluded that she can never wake again until Shion was able obtain the original blueprints from the past Kevin Winnicot, they were able to rebuild her. However the Black Testament manages to sneak on board and steal KOS-MOS's capsule. When the Black Testament telepathically chokes Shion, KOS-MOS awakens to save her. After awakening, KOS-MOS travels with the party for the duration of the party's journey in the past Miltia. When the Red Testament, (revealed to be Kevin) orders KOS-MOS to bring Shion to her, she rejected his commands and directives as she is now programmed to follow Shion only. She then knocks Shion out and the two made their escape back to the Elsa. KOS-MOS later accompanies the party to Merkabah, the hijacked Durandal and Abel's Ark.

In the Underground Ruins, Shion decides to awaken Mary Magdalene within KOS-MOS, causing her eyes to turn blue permanently. T-elos then confronts KOS-MOS again with the intent of assimilating her consciousness into herself, but this time KOS-MOS was able to defeat her and absorb her instead. Within the central chamber where Zarathustra rests, after Shion refuses to use her key to activate Zarathusta, Wilhelm then attempts to use KOS-MOS to activate it for her, only for her to destroy the key, causing Zarathustra to go out of control. In the ending, Mary's spirit leaves KOS-MOS and enters Nephilim. KOS-MOS decides to stay behind to fend off the Gnosis while chaos and Nephilim use their power to send Michtam to Lost Jerusalem, ultimately sacrificing herself to give them the time they need to complete the task. Her upper torso is last seen floating in space drifing toward Lost Jerusalem.

Xenoblade Chronicles 2[edit]

KOS-MOS reappears as a Rare Blade in Xenoblade Chronicles 2. She is an extremely hard to get, as there is only 0.1% chance of obtaining her. She is of the Attacker class and uses Ether Cannons in combat. She is the only non-DLC Rare Blade to have the light element. Her awakening animation depicts her awakening from her pod, similarly how she awoken during the Gnosis attack on the Woglinde.

Artificial Intelligence[edit]

While at the farthest point of the 7th Perimeter Skyport, the party encounters a great number of Blade Bots that had gone berserk after the Marsanes, their command center, went done. At first, the party tries to defeat them all, though the sheer number of enemies proves to be too much to handle. Despite the party deciding to withdraw, KOS-MOS instead decides to annihilate all enemies at once with an X-Buster, leaving only a few stragglers for the party to deal with.

After the battle, the party decides to have an audience with the leaders of the nations gathered around the country, who might have been worried by KOS-MOS's attack, starting with Eulogimenos. During the audience with the king of Tantal, the king requests that the party takes Zeke's first cousin, Astelle, with them while visiting the other leaders. The king was able to convince her to give up on going to the Land of Morytha in favor of traveling around Alrest instead. After Astelle and the prince bicker about how she should call him, she expresses interest in KOS-MOS, wanting to tinker with her.

While on their way to have an audience with Niall, the party is attacked at Hardhaigh Dock, Lv. 2 by more berserk Blade Bots. KOS-MOS fires another X-Buster, annihilating all but two of the artificial Blades. After the party finishes dealing with the situation, Astelle fires a salvo of questions at KOS-MOS about her power, the latter refusing to answer for the most part.

After their audience with the Ardainian emperor, who intends to work with Tantal and Uraya to deal with the Blade Bot issue, Astelle asks the party to bring her to the Land of Morytha. She and Zeke argue for some time, the former trying to bring KOS-MOS into the argument, before Rex decides to concede to the Tantalese girl and bring her to the Land of Morytha.

While Astelle searches around the debris inside the Fallen Skyscraper, under KOS-MOS's guard, she finally finds what she was looking for. While running back to the Blade, she is attacked by a Dagra Guldo that descended from the ceiling. The Guldo fires an Elemental Beam that is intercepted by KOS-MOS, who orders Astelle to hide while she and the party deal with the enemies.

After the party dispatches the Guldos, Astelle confirms she found what she was looking for and asks the party to come with KOS-MOS to her room in Tantal. In front of her room, she gives KOS-MOS a present, a device that helps the Blade in managing her power, then proclaims herself as KOS-MOS's best friend.


While at the First Low Orbit Station's Storage Area Entrance, Tora, Dromarch, KOS-MOS, and her Driver, admire the view. KOS-MOS asks her Driver what they feel, who can answer one of two things.

Her Driver can express their worries over the World Tree falling, spooking Tora. KOS-MOS answers that impact with Alrest would be possible at a lower altitude but not at their current position, which would remain stable. While the Nopon is reassured for a short time, Dromarch wonders how they would get back down to Alrest. KOS-MOS answers once more, saying that they would either "remain in orbit for all eternity" or "fly off into outer space". Her reassurance that she would do all she can to stop that from happening works little on Tora, who learns that he is last in KOS-MOS's list of priorities.

Her Driver can wonder how the World Tree was constructed. KOS-MOS answers with a step-by-step process, which the party understands very little of. Her Driver wonders how she acquired this knowledge, which the Blade is unsure of, as the data exists independently from her memories. As such, she is unable to know who implanted the information or their purpose.

Blue-eyed KOS-MOS
KOS-MOS permanently awakened as Mary

Occasionally KOS-MOS's eyes turn blue, usually whenever Shion is in some sort of danger. During this time, KOS-MOS develops a human personality. The first time it occurs is when saving the Elsa from a swarm of Gnosis with X-BUSTER. In the Underground Ruins, after Shion awaken Mary within KOS-MOS, her eyes turn blue permanently. Additionally, after absorbing T-elos, Mary's original memories underwent a transformation that resulted in a new personality. However when KOS-MOS rejects the Eternal Recurrence, her eyes turned back to red, although her human personality remains.


  • Whenever KOS-MOS awakens as Mary, her eyes turn blue.
  • KOS-MOS's serial number is 00-00-00-00-1.
  • Both KOS-MOS and T-elos are modeled after Mary Magdalene.

As a party member[edit]

Episode I[edit]

Main article: KOS-MOS/Gameplay (XS1)

Episode II[edit]

Main article: KOS-MOS/Gameplay (XS2)

Episode III[edit]

Main article: KOS-MOS/Gameplay (XS3)

Xenosaga I & II[edit]

Main article: KOS-MOS/Gameplay (XS1&2)

Xenoblade Chronicles 2[edit]

Main article: KOS-MOS/Gameplay (XC2)

As an NPC[edit]

KOS-MOS can be found at a random location in Garfont Village after Rex takes over the Merc Group, provided she is not equipped to her Driver or sent on a Merc Mission. The specific locations she may be found at are listed here.


My maintenance is fully complete, Master.


Episode I


An armored female android developed by the interstellar conglomerate, Vector Industries.

She is comprised entirely of mechanical parts, a rarity in an age of advanced Realian technology. The basic tenet to which she adheres to is based on logic, probability, and completion of her mission above all else. She also unconditionally protects Shion, her creator.

She is equipped with a "simulated personality OS" to aid in communication, and though her speech conveys her role as an android in service to humans, her tendency to put logic and probability first makes her quite difficult to manage at times.

The name KOS-MOS is a general acronym to denote an anti-Gnosis tactical system. It stands for "KOS-MOS Obey Strategic Multiple Operations Systems."

Episode III

KOS-MOS [Archetype]

KOS-MOS -Archetype- Database Thumbnail XS3.png

A being designed and constructed for the purpose of monitoring Shion.

In Jungian psychology, the archetype is the portion of the mind which is passed on hereditarily. It is said to be the model upon which the unconscious, instinctive workings of the mind are structured.

The archetype was designed and constructed for the purpose of monitoring Shion. All of its functionality was contained within the core unit, which was later recovered and installed in KOS-MOS.

Kevin, needing to die in front of Shion's eyes, had secretly installed a program into the archetype causing it to go out of control. The program was later engaged via the startup key which Kevin had given to Andrew.

KOS-MOS [Test Type]

KOS-MOS -Test Type- Database Thumbnail XS3.png

Frame created by Shion and the others based on the Archetype.

The frame put together by Shion and the others after transplanting the core module of the partially-destroyed Archetype into a spare frame. Christened KOS-MOS Version 1.

Partially in order to shake off memories of the incident when the Archetype went out of control, the exterior of this model's design was much closer to that of a human body. Several monitoring sensors were installed inside the body to record real-world data.

KOS-MOS [Combat Frame]

KOS-MOS -Combat Frame- Database Thumbnail XS3.png

Frame created by the Second R&D Division.

The frame created by the Second R&D Division on Second Miltia during the KOS-MOS OS tests. Vector staff refer to it as Version 2.

In order to shield her internal organs from shocks delivered to the outer body during combat, her body was filled with fluorescent blue anti-G gel. The Hilbert emission device, which had taken the form of a visor in Version 1, was miniaturized and installed into her forehead. Her body was designed with the implementation of the Tertiary Weapons System in mind; its resilience was increased dramatically.


KOS-MOS Database Thumbnail XS3.png

KOS-MOS, having awoken as Mary Magdalene.

A female-shaped battle android developed by the interplanetary conglomerate Vector Industries. A being created entirely from mechanical parts, exceptionally rare in this era of advanced Realian technology.

Prioritizing the three fundamentals of logic, efficiency, and duty, she protects her creator Shion unconditionally. She is equipped with an Artificial Personality OS" in hopes of facilitating smooth communication with others, and her tone is that of an android subservient to humans. As she is actually just prioritizing logic and efficiency, however, she can often be difficult to handle.

KOS-MOS is the term applied to the entire anti-Gnosis combat system; it stands for "Kosmos Obey Strategical Multiple Operation Systems."

Why were KOS-MOS's repairs that took place on the Miltia of the past within Shion's deep memory, a type of imaginary space, reflected in the real world? One reason is the fact that actions in one portion of the U.M.N., the deep memory--that is to say, the collective unconscious-- are equivalent to those in the real world according to one definition, where the difference is strictly subjective-- brought about by the observer's recognition of it as such.

Though KOS-MOS awakened as Mary Magdalene as a result of T-elos' defeat, Mary's original memories and characteristics have undergone a transformation, leading to the creation of an entirely new personality which is both Mary and not Mary at the same time. This is fundamentally analogous to Sakura's transformation into MOMO.

The battle over, KOS-MOS falls into an eternal sleep and drifts, like the passage of time, through the emptiness of space. A blue light penetrates her battered and faded figure. Perhaps that light will be the cause of a new awakening.



KOS-MOS Encyclopedia Thumbnail XSF.png


ヴェクター第一開発局、対グノーシス専用ヒト型掃討兵器KP-X。Kosmos Obey Strategical Multiple Operation Systemが正式名称で、訳すと"秩序に従属する戦略的多目的体系"となり、頭文字を取ってKOS-MOSと呼ばれる。ヴェクター関係者を保護することが義務づけられ、戦闘など非常時に於いても、それは優先させる。感情プログラムは造物主たる人間が使いやすいようプログラムさせていると言いながら、素子構造は人脳を忠実に再現していることから、独自の感情が生まれる可能性が暗示されている。最大機能は"ヒルベルトエフェクト"で、グノーシスを固着化させる。開発計画担当幹技師であるシオンの知らない兵装(グノーシスを吸収する)があることや、シオンとは違う者の命令で行動している気配が感じられ、何か特別の任務を持っているとも思われる。

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Archetype Encyclopedia Thumbnail XSF.png



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Xenosaga I & II






KOS-MOSとは、対グノーシス用に開発された戦闘システムの総称であり、正式名称は"Kosmos Obey Strategical Multiple Operations Systems"直訳すると"秩序に徒属する戦略的多目的制御体系"となる。

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KOS-MOS 【アーキタイプ】




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KOS-MOS 【模擬戦用筐体】




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  • In the Japanese version of Xenosaga and Xenoblade Chronicles 2, KOS-MOS is voiced by Mariko Suzuki, who also voices T-elos in Xenosaga Episode III and Xenoblade Chronicles 2.
    • Along with KOS-MOS' Japanese voice actor, her English voice actor in Xenosaga Episode I and Xenosaga Episode III, Bridget Hoffman, also voices T-elos in Xenosaga Episode III.
  • In the English version of Xenoblade Chronicles 2, KOS-MOS is voiced by Caitlin Thorburn, who also voices Nim and T-elos in Xenoblade Chronicles 2.

In other languages[edit]

Language Name Meaning
United Kingdom flag.svg English KOS-MOS
Japan flag.svg Japanese KOS-MOS
France flag.svg French KOS-MOS
Germany flag.svg German KOS-MOS
Spain flag.svg Spanish KOS-MOS
Italy flag.svg Italian KOS-MOS
China flag.svg Chinese (simplified) KOS-MOS Re: (XC2)
Taiwan flag.svg Chinese (traditional) KOS-MOS Re: (XC2)
South Korea flag.svg Korean KOS-MOS Re: (XC2)


Main article: KOS-MOS/Gallery