Xenosaga Wiki

I do not exist for your pleasure.
—KOS-MOS in the Y-Data

KOS-MOS is an armored android robot combat weapon with an artificial intelligence to fight the Gnosis.

Created by Kevin Winnicot and administrated by Chief Engineer Shion Uzuki, KOS-MOS was developed by the interstellar conglomerate Vector Industries First R&D Division for the Galaxy Federation's Zohar Project. She is the magnum opus of the eponymous KOS-MOS Project.

KOS-MOS's Image Gallery

Design, abilities and functions[]

I think if we have hearts and minds, then it's evident that she would have them as well.
Dr. Juli Mizrahi to Shion on KOS-MOS


She is composed of entirely mechanical parts, a rarity in the age of advanced Realian technology which have replaced androids. KOS-MOS' existence is both anachronistic and futuristic.

KOS-MOS has an advanced CPU (central processing unit).

KOS-MOS has long blue hair, red eyes which occasionally turn blue, and a layer of realistic-looking artificial prosthetic skin.

The source of KOS-MOS' power comes from U-DO by using the original Zohar as a door. Unfortunately, this means that every time KOS-MOS uses her abilities, Shion reacts to U-DO and loses her life force.

Shion implies that KOS-MOS' existence, at least in the beginning of the series, is a government secret.[1]

Software (personality)[]

KOS-MOS saving Shion on the Elsa Evolution.

KOS-MOS is equipped with a "Simulated Personality OS", or artificial intelligence (AI), to aid in communication. Though her speech conveys her role as a robot in service to humans, the basic tenet to which she adheres is based on logic, probability, and completion of her mission above all else in all situations. She also unconditionally protects Shion. The algorithms she is programmed with do not support the comprehension of illogical human thought.

KOS-MOS also possesses a wireless U.M.N. connection and can instantly answer any question asked - for example, if KOS-MOS is asked what the capital of the Galaxy Federation is, KOS-MOS will reply "Fifth Jerusalem". During the dive into MOMO's subconscious domain, Shion is confused about how Albedo could've been attached to Jr.'s back during fetal development, and KOS-MOS explains that occasionally conjoined twins can share portions of their internal organs.[2]



Shion: "Do you feel sad or anything?"

KOS-MOS's elemental data structure duplicates that of a human brain. She appears to be emotionless, but throughout the series, evidence indicates that this is not entirely true. A predetermined set of emotions has been hard-coded into her emotion module to better facilitate interactions with humans. She will emit an expression such as sadness only when that response is deemed necessary. However, if the emotion module of her program has determined that it is not currently necessary, she will not emit an expression.

KOS-MOS has AAA class encryption. It is a designation given to areas requiring the highest levels of restricted access. As one of the highest classified components of Project Zohar, KOS-MOS falls under this designation. KOS-MOS' importance to this project is evident in Jr.'s comment that the only other entities with that class of restriction would be the "Federation government's motherframe, or the U.M.N. operating system."


Ye shall be as gods.

  • The name 'KOS-MOS' is a recursive acronym used to denote an Anti-Gnosis tactic system. It stands for "Kosmos Obey Strategical Multiple Operation System". Another translation is a "strategical multiple-operation control system that obeys the rules of order".
  • Her development codename is "KP-X", and she is self classified as a "Special Humanoid Anti-Gnosis Annihilation Weapon".
  • Her serial number is "000000001".
  • Her login password is "Ye shall be as gods", which is Genesis 3:5 from the Bible.
  • Her system is NATARAJA, referring to the depiction of Shiva as a calm-faced divine figure in the act of dancing.

Xenosaga I. KOS-MOS (7 Abilities)

KOS-MOS killing Gnosis in combat.

Combat, weapons and abilities[]

KOS-MOS has significant powers believed to be superior to all other party members, with the possible exception of Jr.'s Red Dragon Mode. In addition to superhuman strength and speed, her body is formed from some sort of highly advanced nanomachines that allows her to morph parts of her body (specifically her arms) into various energy projectile and melee weapons. This body is also able to self-repair and is very durable though not indestructible, and she is also protected by a force-shield.

KOS-MOS (Ver.4) using her machine guns.

She also possesses the ability to summon specialized weapons such as the F-G-SHOT gatling guns and her famous F-SCYTHE and equipment without the use of the U.M.N., due to the usage of a Transfer System.

She has a long-range sensory array, the D.S.S.S. (Double Slot Sensory System, read as "D-triple-S") and CPU that either rivals or exceeds even those possessed by 100-Series Observational Realian. The D.S.S.S. detects Gnosis in the imaginary realm.

KOS-MOS using the Hilbert Effect on Gnosis.

She also possesses the Hilbert Effect, which is used to draw the Gnosis into the physical plane, allowing the party to be able to physically combat them. Once the Hilbert Effect has dissipated, any Gnosis previously affected will return to their state of invulnerability. Ultra Wide-Range Hilbert is the deployment of the Hilbert Effect over an extremely large area. Ordinarily, the range of KOS-MOS' Hilbert Effect is set to cover a radius of about 300,000km. However, when Shion witnessed the impending massive swarm of Gnosis, she decided to enlarge the effective range to a radius of several hundred AU (astronomical units).

KOS-MOS has a Secondary Weapon System which is KOS-MOS's main combat equipment; this refers to her current armament, frame material, and substitute armor materials. The Secondary Weapons System made experimental use of a PT cartridge-type phase transfer cannon; the limited unit size, however, meant that the places and situations in which it could be used were restricted. For this reason, the Tertiary Weapons System, with a phase transfer unit installed as standard equipment, was produced on Second Miltia.


Xenosaga Episode II HD Cutscene 15 - Tertiary Weapons System - ENGLISH

The Tertiary Weapon System.

KOS-MOS has one last optional weapon system called the Tertiary Weapon System, which is seen periodically throughout the series. It was designed by Kevin while he was still alive and built at Vector Second R&D Division on Second Miltia. They consist of a set of energy wings, a pair of energy cannons and other attachments meant to be fitted onto her, with the wings and cannons being part of a Phase Transfer Cannon. Because the phase transfer cannon units are made to be as compact as possible, the recoil when the are fired is very high; the Version 2 KOS-MOS Combat Frame is required to fire these weapons. The PT cartridge-type phase transfer cannon used by KOS-MOS when the Song of Nephilim appeared had been created as a test bed for these cannons. When the cannons are fired, a cooling field in the shape of glowing wings is created behind the unit. While wearing this gear she is shown in a premonition flying through space at sub-light speed and then confronting U-DO above an unknown planet (presumably Miltia) and the exchange that follows destroys many galaxies. The "Third Armament" as it's also known makes a real-time appearance in Episode II on the Omega System. KOS-MOS uses this equipment to protect Shion and the party from a U.M.N. Phase Transfer Cannon fired by Proto Omega.

KOS-MOS uses X-BUSTER against Gnosis.

KOS-MOS possesses several black box components left behind by Kevin since the current KOS-MOS is essentially the archetype resurrected. There are still many 'black boxes" to be revealed but two include her potent "X-BUSTER" a weapon that fires powerful energy beams from her abdomen as well as absorb Gnosis, and components that her give her some kind of self-awareness. KOS-MOS also has some form of energy manipulation tied to the Zohar.

Finally, KOS-MOS also has the ability to dance.[4]

Blue-eyed KOS-MOS[]

KOS-MOS changes eye color in Episode I.

A human-like alternate persona appears occasionally in the form of a blue-eyed KOS-MOS. Blue-eyed KOS-MOS appears to be more powerful than red-eyed KOS-MOS and talks in a more human-sounding voice. This form of KOS-MOS only seems to appear at times when Shion is in extreme danger and plays the role of Shion's guardian. Shion has not directly seen KOS-MOS in her blue-eyed form and is oblivious to this second persona's existence until Episode III.

Blue-eyed KOS-MOS has made four appearances in Xenosaga:

Blue-eyed KOS-MOS (Mary) in Episode III.

  • Wiping out a fleet of Gnosis surrounding the Cathedral Ship with her X-BUSTER attack. Blue-eyed KOS-MOS also asked Shion during her first appearance in Episode I, "Will feeling pain make me complete?", though Shion couldn't give her an answer because she could not hear KOS-MOS' voice in the vacuum of space.[5]
  • Saving the Elsa from burning up in the Second Miltian atmosphere in Episode I.
  • Saving Shion and Allen Ridgeley in space from being killed by Voyager, the Black Testament, Episode II.
  • Saving Allen and Shion in the finale of Episode III.


Mary Magdalene on Lost Jerusalem[]

Mary Magdalene listens to Jesus' sermon.

Six thousand years ago, Mary and Yeshua were disciples of Jesus. Mary, Yeshua, Jesus and their followers were persecuted by Wilhelm, who as Guardian of the Lower Domain saw them and their power as a threat to life in the Lower Domain. Since Anima is the failsafe power which must destroy the Lower Domain in order to protect the whole universe, and considering that the followers of Jesus and Mary all had the ability to react with Anima (similar to the abilities the Testaments and most party members), Wilhelm feared the failsafe's activation. As a result, he persecuted Jesus and his disciples.

Mary Magdalene cries in sorrow.

Mary is also responsible for the construction of Zarathustra; she wanted to use it in order to save the universe from destruction (similarly, Dmitri Yuriev will later attempt to act with for his partially selfish intentions), but she failed. Zarathustra ended up falling into Wilhelm's hands while the situation for the universe degraded.

Despite very little is known about her life, she was extremely close to the previous incarnation of Shion Uzuki, who was called the Maiden of Mary, and of chaos, at this time known as Yeshua. Shion is required to release the power of Animus, meaning both Mary and Shion need to exist for this power can be used to its full extent. Nevertheless, Shion (as the Maiden) died in front of Mary, who at that moment had lost all of her power by dividing Yeshua's Anima, rendering her helpless. This is apparently the biggest regret in Mary's life.

Mary Magdalene's body in her coffin.

In order to prevent the destruction of the Lower Domain by the power of Anima, Mary divided the power of Anima into twelve Vessels of Anima. Doing this cost her her life, but not before she saw Shion's death. Mary's death caused her consciousness to be scattered across the Collective Unconscious in the Imaginary Number Domain of the Lower Domain, which the U.M.N. would use as network infrastructure.

People who cared for Mary chose Rennes-le-Château to hide this vessel from their enemy, most likely Wilhelm. They also chose this place as a location to store Mary's body in a coffin full of flowers. Six thousand years later her body would still be intact. Even though Wilhelm succeeded in stealing the Vessels of Anima later, he, for mysterious reasons, failed to take Mary's body and had to wait for Rennes-le-Château to appear in space to retrieve it.

KOS-MOS Project (creation of KOS-MOS Archetype)[]

Kevin Winnicot and Shion Uzuki.

Wilhelm, in order to initiate the Eternal Recurrence, required the power of Animus. In order to do this, he needed two elements: the body of Mary resting at Rennes-le-Château and the Maiden of Mary's reincarnation, Shion Uzuki, who is needed for Mary to fully use her powers and to revive Mary's consciousness, as well as a body to complete Mary's revival. Due to the body being impossible to reach, an artificial vessel would be created for her consciousness: KOS-MOS.

Her consciousness must progressively awake inside of her through her bond with Shion Uzuki, one of the co-creators of KOS-MOS as well as Kevin's girlfriend. Of course, Wilhelm couldn't directly tell the Vector development team about KOS-MOS' purpose (Mary Magdalene), so he entrusted this information to Kevin, and Kevin created KOS-MOS under the guise of the purpose of defeating Gnosis. Being the CEO of Vector, Wilhelm could provide Kevin with all the resources he would need.


Memories of Days Past

Kevin decides on a female form.

Kevin completed making the initial designs and blueprints of an anti-Gnosis battle android, the ideal android being KOS-MOS while he was working for U-TIC. The basic KOS-MOS Archetype was completed while Kevin and Shion were working at Vector Industries. Kevin wanted KOS-MOS to have a female form as opposed to a male form, since he believed men were "capable of nothing but destruction and conquest." He wanted KOS-MOS to symbolize hope and healing, as well as a creator and protector. A female form would also be more suitable for Mary Magdalene.

Archetype's Rampage[]


Xenosaga Episode I HD Cutscene 056 - The KOS-MOS Incident - ENGLISH

KOS-MOS goes on a rampage, killing Vector and U-TIC employees.

In T.C. 4765, to intensify the bond between Shion and KOS-MOS, Kevin arranged to die at the hands of KOS-MOS's archetype. In disguise, Kevin handed over the start-up control to Andrew Cherenkov. Andrew in turn led his U-TIC unit and raided the Vector's Second Division on planet Carioca, intent on seizing the KOS-MOS archetype. During this, the archetype booted up and went on a murder spree. During the rampage, Kevin was stabbed through the chest by the KOS-MOS archetype, and Shion put an end to the Archetype using a gun.

In total, five Vector Industries researchers and eight members of the U-TIC Organization died. What was notable was that all who survived were those who managed to avoid being attacked in the first place. There were no cases of someone being attacked by KOS-MOS and getting by with just an injury.

Kevin sacrifices his life to protect Shion from the berserk KOS-MOS Archetype.

Shion survived the attack (Allen Ridgeley was away on a business trip) and decided to continue the project without Kevin. This was the greatest accident surrounding the development of KOS-MOS.

In terms of the KOS-MOS development plan, the greatest loss was that of the chief developer, Kevin Winnicot. Due to this loss, the development of KOS-MOS was greatly set back. Even the current chief developer, Shion Uzuki, does not understand everything about the interior that has been sealed off due to the black boxes. Only Kevin understood all of that. This left Shion the task of creating KOS-MOS' final form, as well as making KOS-MOS her only link to Kevin.

Shion destroys KOS-MOS with a headshot.

KOS-MOS's new frame was put together by Shion and the others after transplanting the core module of the partially-destroyed Archetype into a spare frame. Partially in order to shake off memories of the incident when the Archetype went out of control, the exterior of KOS-MOS's design was much closer to that of a human body. Several monitoring sensors were installed inside of the body to record real-world data.

Encephalon testing[]

A Vector VR-2000 Encephalon device.

To avoid repeating the same mistakes that led to tragedy, only the start-up experiments in the Encephalon were repeated when testing KOS-MOS's new frame. While the virtual missions and tests were comparable to what KOS-MOS would be like in the field, the abilities of KOS-MOS's physical body remained untested, leaving her effectiveness as an anti-Gnosis weapon in the realm of theory.[1]

Xenosaga Episode I: Der Wille zur Macht[]

KOS-MOS Ver. 1
(model from Episode III).

Shion proceeds with a test experiment on KOS-MOS. After having completed KOS-MOS, Shion and her team are attacked by the Gnosis on the ''Woglinde''. KOS-MOS is self-activated suddenly and helps those on the Woglinde evacuate. KOS-MOS saves Shion from a Gnosis attack, and tells Shion and Allen that her assigned duties are to verify and preserve the object stored in the hangar, as well as protect Vector staff members.


Lieutenant Virgil's Death

KOS-MOS kills Luis Virgil to save Shion.

Unfortunately, during the escape, Galaxy Federation Lieutenant Luis Virgil is shot and killed by KOS-MOS during these events; this, according to her, was necessary due to the fact that it would increase her ability to protect Shion. The Gnosis also escape with the Zohar Emulator.

After the Woglinde is destroyed, KOS-MOS ended up on the hull of the Elsa, a Kukai Foundation scavenger ship exploring the ruins of the Woglinde, and threatened to smash open one of the bridge's windows and expose the crew to the vacuum of space if they did not take her aboard. KOS-MOS refused to take Shion's pod on the Elsa, considering that she would be saved soon by a Federation ship. Shion tested KOS-MOS's logic by threatening suicide if KOS-MOS did not take her with her.

Eventually, Shion, Allen and Andrew Cherenkov also arrived on the Elsa. KOS-MOS is berated by Shion for abandoning them and trying to go to Second Miltia. On the Elsa, the group encounters a mysterious boy, chaos, before asking Captain Matthews to escort them to Second Miltia. KOS-MOS is tuned in her service module in the Elsa's maintenance lab by the hangar because "due to the limitations of the test-use condenser" her "energy reserves are almost depleted" and she wishes to "receive a co-generator bypass in order to replenish them", and requests that Shion adjust her malfunctioning sensors. Cherenkov recognizes KOS-MOS as the archetype from before and almost shoots her, but refrains at the last second. Not long later, Ziggy and MOMO Mizrahi arrive on board the Elsa.


Xenosaga Episode I HD Cutscene 085 - X-BUSTER!!! - ENGLISH

KOS-MOS using X-BUSTER against a fleet of Gnosis attacking the Elsa.

Eventually, after a series of events (exploring the Dock Colony and Cathedral Ship), the Elsa was attacked by Gnosis; KOS-MOS didn't understand what was happening to her and said "Will feeling pain make me complete?". Shion, however, was unable to hear KOS-MOS's (Mary Magdalene's) voice in the vacuum of space. She then used her X-Buster to absorb an entire Gnosis fleet, astonishing Shion and all those who saw it, as this ability was not in her original function. In the anime adaption, chaos is shown as the one who allowed KOS-MOS (Mary Magdalene) to access her full power.

Later, the Galaxy Federation places charges on the Kukai Foundation for the destruction of the Woglinde, due to some manipulation and framing by U-TIC Organization officials and insiders doctoring video footage of the Durandal attacking the Woglinde. In order to prove innocence, Shion leads a dive into the Encephalon to find KOS-MOS' black box, which will prove that the Gnosis were actually responsible for the Woglinde's destruction, since KOS-MOS stores unalterable automatic video recordings in her memory bank data with AAA level security.


Ye Shall Be As Gods

Nephilm warns Shion of KOS-MOS and U-DO.

In the Encephalon, the party relives Shion's and Jr.'s difficult childhood memories, including the Miltian Conflict. Shion is encountered by Nephilim Verum and Febronia, who explains that a time will come where KOS-MOS will encounter the wave existence U-DO. During this scene, which is a "vision of the future", KOS-MOS is seen wearing her Tertiary Weapon System and confronts U-DO above an unknown planet. The exchange that follows destroys several . Febronia also tells Shion in the near future, Shion will free her "sisters", Cecily and Cathe. Febronia also states that all factions involved must travel to Old Miltia.

KOS-MOS crucified with cables and wires in front of an tomb in the Encephalon.

Still in the Encephalon, Shion then finds KOS-MOS crucified in a cave (Rennes-le-Château), in front of a tomb which belongs to Mary Magdalene's. When Shion awakens KOS-MOS with her password "ye shall be as gods", KOS-MOS is engulfed with light radiating from her body, and KOS-MOS disarms the Encephalon's subconscious domain protection.

During the Gnosis assault on the Kukai Foundation, Shion orders to KOS-MOS to use the Hilbert Effect, and the party proceeds to evacuate the Kukai Foundation. The evacuation is successful, however, in the confusion surrounding the attack, Albedo Piazzolla kidnaps MOMO and brings her to the Song of Nephilim.

Shion, the party and KOS-MOS use a Phase Transfer Cannon to bring the Song into real space. Shion's party enter the Song and defeat Albedo. Albedo escapes, however.


Xenosaga Episode I Escape

KOS-MOS stays to disassemble the Proto Merkabah.

On the Proto Merkabah, the party encounters Albedo, who summons a Gnosis called Sophie Peithos to "test" the party and give him time to escape. Albedo sets Merkabah on a collision course with Second Miltia, which the party decides to stop by breaking the space station into thousands of pieces, vaporizing them before impact. KOS-MOS offers to stay behind to initiate the detachment sequence, but tells Shion that she has no intention of remaining. As the Proto Merkabah detaches, Shion uses her intuition to locate KOS-MOS and Ziggy helps Shion pull KOS-MOS into the Elsa.

However, during re-entry, the Elsa's heat shield begins to disintegrate; KOS-MOS leaves the Elsa's hangar while telling chaos, "Relinquish your pain unto me." KOS-MOS jumps out in front of the Elsa in an attempt to shield it using her energy field. Shion is worried about KOS-MOS being incinerated and KOS-MOS replies, "I am happy... to be of service." While holding her position, KOS-MOS' eyes turn blue, resonating with Mary Magdalene, briefly morphing her into a powerful being to prevent the Elsa from being destroyed using a shield of gigantic ethereal wings.

After the Elsa's descent into Second Miltia's atmosphere, Shion is relieved that KOS-MOS survived. Back on the Elsa, KOS-MOS approaches Shion in the diner, saying her mission is complete. Shion welcomes KOS-MOS's safe return and the group flies to Second Miltia.

Xenosaga Episode II: Jenseits von Gut und Böse[]


In Episode II, KOS-MOS has little effect on the plot and is simply a supporting character.

At Second Miltia's Vector Industries headquarters, Shion, Allen and KOS-MOS are briefed of the increasing Gnosis threat. KOS-MOS receives a new frame created by the Second R&D Division on Second Miltia during the KOS-MOS OS tests. 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.

Her data is sent to the MOMO's Encephalon dive while at Vector's Second R&D Division, allowing her to fight in battle against the Gnosis and Albedo while not being physically present.

When Shion and Allen steal E.S. Dinah, they are attacked by Voyager in E.S. Dan. Hearing Shion's cries for help, Mary Magdalene's power allowed KOS-MOS to activate without a battery. Using her space bike, the Mobile Dinah Interface, she used her powers combined with those of E.S. Dinah to destroy the fleet attacking Shion and saved her from being destroyed by Voyager. Since then, KOS-MOS pilots Dinah.


Xenosaga Episode II HD Cutscene 68 - Feb's Sisters Awakening of Omega - ENGLISH

KOS-MOS sets Cecily and Cathe free.

In Labyrinthos on Old Miltia, KOS-MOS destroys Cecily and Cathe for Shion and Febronia, freeing them from their suffering.

When Albedo links with the Zohar/U-DO in the Ω System, KOS-MOS transforms and shields Shion and the party to protect them from the waves of the space-time anomaly.

After the events of the game, KOS-MOS and Shion return to Second Miltia.

Xenosaga: A Missing Year[]

KOS-MOS (ver 3) rescues Shion in Ars Nova.

In T.C. 4768, Gnosis raid the S.O.C.E. lab due to an increase in Gnosis Terrorism. Shion and KOS-MOS rush to the lab to rescue the survivors. However, in the process, Scientia agent Doctus kidnaps Almadel and half damages KOS-MOS. After the incident, KOS-MOS is sent for repairs and is upgraded from version 2 to version 3 by Vector Industries.

Later, KOS-MOS rescues Shion from a Gnosified Almadel in Ars Nova, one area of S-Division within the U.M.N. sealed by Vector Industries. KOS-MOS is equipped with a new exoskeleton. Unfortunately, despite KOS-MOS and Jin Uzuki's efforts, Almadel still dies.

After an emotional breakdown from Shion, KOS-MOS helps her up by giving her a hand.

Xenosaga Episode III: Also sprach Zarathustra[]

Shion left Vector, and more Gnosis attacks are occurring, termed Gnosis Terrorism. Unfortunately, because KOS-MOS is owned by Vector, Shion could not keep KOS-MOS with her, and Allen looked after KOS-MOS for Shion.


Xenosaga Episode III - Chapter 2 - CAT Testing Ground - KOS-MOS vs. Omega

KOS-MOS fights Ω Res Novae and loses.

Vector Industries decides to terminate the KOS-MOS program in favor of the newer and more advanced T-Weapon Program that resulted in the development of T-elos. Seeing KOS-MOS as an expendable asset, she is used as a live-fire opponent for the new Omega Res Novae machine. In the fight KOS-MOS utilizes nearly every attack in her arsenal including her X-BUSTER but is unable to destroy the enormously larger Omega. She appears to have some effect as Omega malfunctions during the fight, and it is forced to cancellation by the S.O.C.E. When T-elos is demonstrated as being superior, S.O.C.E. decides to pour their resources into T-elos' development. They scrap KOS-MOS and place her in a garbage compacter.


KOS-MOS (CAT Testing Ground)

KOS-MOS is rescued by Shion.

Juli Mizrahi deduced that only KOS-MOS has the ability to break open the hypersphere of Rennes-le-Château for them to rescue the Elsa. The team made their way to Fifth Jerusalem and met up with Shion. Together, they broke into the Federation compound to salvage KOS-MOS, which had been dumped at the scrap yard. With KOS-MOS's help, they managed to break into Rennes-le-Château and made contact with the Elsa. KOS-MOS continues to travel with the group, still piloting Dinah.


KOS-MOS vs. T-elos (Ancient Temple Tomb)

T-elos on Rennes-le-Château.

In Rennes-le-Château, KOS-MOS engages with T-elos in a pitched battle and KOS-MOS is completely dominated by T-elos. KOS-MOS only manages to connect with a single attack against T-elos while taking severe damage herself. Finally T-elos utilizes her Phase Transfer Cannon, which KOS-MOS attempts to deflect. Her effort fails and she sustains crippling damage from the attack. T-elos completes the fight by driving her heel through KOS-MOS chest as she lay on the ground. As KOS-MOS lay "dying" Shion has a vision of Mary Magdalene as she stares at T-elos.


Xenosaga Episode III - Chapter 4 - Dabrye Mine - KOS-MOS's Eternal Sleep

KOS-MOS is heavily damaged.

When KOS-MOS is examined by Shion, Allen, Professor and Scott, they come to the conclusion that KOS-MOS will never again be operational due to the severe damage. This outcome changes when Shion is able to obtain the original design data from a past Kevin Winnicot (unknown to him) while masquerading as U-TIC personnel. With the assistance of the Professor's Erde Kaiser technology, KOS-MOS is rebuilt into her Version-IV form. The new KOS-MOS is considerably more powerful.

KOS-MOS Ver.4, rebuilt by Professor and Scott.

KOS-MOS awakens to protect Shion when she is attacked by the Testament Voyager. Her rebuild also grants KOS-MOS the ability to reject the commands and directives of Kevin Winnicot, something she was incapable of before.

It eventually becomes clear that KOS-MOS was the prototype for T-elos, who in turn was intended to serve as the vessel for the resurrection of Mary Magdalene. KOS-MOS came to be the repository for Mary's spirit, while T-elos was constructed from the remains of Mary's body. In order for the resurrection to be complete, one would have to destroy the other. All of this fit in with the plan master-minded by Wilhelm to use Mary Magdalene's power to operate Zarathustra and "reset" the progression of time in the universe back to an earlier stage. It was this very activity that lead to the creation of the Gnosis as eventually human spirits began to reject the repetitive existence.

KOS-MOS has a final showdown with T-elos as Shion and the group make their way to Zarathustra on Michtam. At first the fight proves a stalemate, as T-elos is unable to completely overwhelm the rebuilt KOS-MOS as she did before. In the second fight KOS-MOS is able to completely evade T-elos attacks, but fails to land any of her own.


KOS-MOS vs. T-elos (Underground Ruins)

T-elos recombines with KOS-MOS.

Finally T-elos resorts once again to her Phase Transfer Cannon. As before KOS-MOS attempts to deflect the blast, and this time is successful doing so with only one hand. T-elos then fires a second, much more powerful shot. KOS-MOS answers by revealing her own Phase Transfer Cannon and returning fire. The two weapons meet, with T-elos weapon being overcome. T-elos is then encased in the array, and KOS-MOS utilizes a knife to shatter the globe. This is sufficient to disable T-elos or perhaps even kill her as she does not move or speak afterward. Following this the two begin to resonate with one another as KOS-MOS kneels and takes T-elos in her arms. T-elos dissipates into particles which are taken in by KOS-MOS.

This completes Mary's resurrection with the merging on body and spirit. The new entity, however, is not a complete recreation of Mary Magdalene. KOS-MOS states that she is both Mary, and not Mary, meaning she received Mary Magdalene's memory and power. When Allen is being tortured with Kevin, KOS-MOS saves Allen which convinces Shion to leave Kevin. After the group defeats Kevin, the Red Testament, they enter the chamber of Zarathustra.


Xenosaga III HD Cutscene 339 - KOS-MOS's Rejection (Zarathustra's Hall) - ENGLISH

KOS-MOS rejects the Eternal Recurrence.

There Wilhelm attempts to command Mary to assist him in activating the device as he has apparently done several times before when he previously reset universal time. This time, however, KOS-MOS refuses and destroys the key to Zarathustra, stating that her name is not Mary, but KOS-MOS. Her eyes change from blue to red. Given that the Perfect Guide states Mary's spirit is KOS-MOS's spirit, this is because Mary's consciousness changed and awoke in some different, just like Kevin said and KOS-MOS/Mary rejected her past and previous identity. A violent battle then ensues as Zarathustra goes out of control.



Shion and KOS-MOS.

After great effort the group manages to overcome Zarathustra. Nephilim then appears stating that her and chaos will begin summoning the troubled spirits of the Gnosis and returning them to the "Land of Origin" also known as Earth. They state that they will be unable to defend themselves while handling this task. KOS-MOS stays behind to protect them in this task. KOS-MOS and Shion share final words where KOS-MOS states that they will see each other again, and that their time apart will be a mere instance in the scope of universal time.

Mary Magdalene / Animus transfers to Nephilim so the Gnosis go to Lost Jerusalem.

KOS-MOS transfers a part of Mary to Nephilim, or rather the Perfect Guide states that only the Animus power was moved to Nephilim, just like chaos transferred his Anima power to Abel. The group then retreats, and KOS-MOS/Mary begins fighting the swarms of Gnosis who attempt to attack chaos and Nephilim. Fearing that not even KOS-MOS can handle the large numbers of Gnosis alone, Jin returns to give her assistance. KOS-MOS is able to destroy a large number of Gnosis before losing an arm while wounding another. Jin manages to finish the particular Gnosis off and the two continue fighting. Jin is killed after being stabbed to death, leaving KOS-MOS to finish protecting the others on her own.

She manages to hold the Gnosis off as chaos and Nephilim approach completion of their task. As they approach completion, they are attacked by a Cathedral Ship type Gnosis. In an act of self-sacrifice to ensure the completion of the task, KOS-MOS energizes her Phase Transfer Cannon and leaps into the cathedral ship creating an enormous explosion. She manages to attain the victory and gives chaos and Nephilim the time to finish.

KOS-MOS's torso drifts to Lost Jerusalem.

At the very end, KOS-MOS is seen in space. Her right arm and both her legs are gone, and what remains of her body is badly damaged. As she drifts, she hears chaos' voice, telling her that apparently the universe still needs them. He then tells KOS-MOS to sleep until they are needed again. KOS-MOS closes her eyes as she drifts through space toward the sun rising over Lost Jerusalem.

Given that her last words before detonating herself against the giant Gnosis reference her past as Mary Magdalene and her regret in failing to protect the Maiden of Mary, Shion's previous incarnation, It's safe to assume Mary and KOS-MOS became one identity. This is confirmed again in the Perfect Guide that states that Mary's consciousness resides and is one with KOS-MOS.

Tech Attacks[]

List of Episode I Tech Attacks
Skill Level Description Speed/Wait
R-Blade Default Attack with a sword arm 200/10
R-Cannon Default Attack with a beam arm 200/10
R-Drill Attack with a drill arm 300/30
X-Buster Abdominal spread beam weapon 800/40
S-Chain Causes "Slow", "Dex Down" and "Phy Def Down" on Biological, Gnosis-Type enemies; Causes "Slow", "Dex Down" and "Armor Down" on Mech-Type enemies 300/30
R-Hammer Attack with a hammer arm 400/30
R-Dragon Attack with a dragon arm 400/30


For quotes from Project X Zone, view its respective article on its wiki.

Battle quotes

  • "Target locked on. Commencing combat mode."
  • "Hilbert Effect active. Gnosis materialization complete."
  • "All battle systems are go."
  • "Disabling auto-safety. Destroy all targets!"
  • "Your orders, Shion?"
  • "All systems clear."
  • "The enemies have been exterminated."
  • "My external appearance is down 5%. Shion, I need to be cleaned."
  • "Requesting recovery of HP."
  • "I recommend reorganizing the group."
  • "Shutting down."
  • "Returning to battle."
  • "Charging."
  • "All systems functioning normally."
  • "Engaging with maximum output."
  • "Eliminating enemy threat."
  • "La, serutou, ettal."

Episode I

  • "A predetermined set of emotions has been hard-coded into my emotion module to better facilitate interactions with humans. In order to better facilitate a relationship with you -- Chief Engineer Shion Uzuki of the KOS-MOS Project, Vector Industries First R&D Division -- I will emit an expression such as sadness, only when that response is deemed necessary. However, the emotion module of my program has determined that this is not necessary at this time."
  • "The algorithms I have been programmed with do not support the comprehension of illogical human thought."
  • "Shion, you forget I am not human. I am merely a weapon. You of all people should be well aware of that fact."
  • "What is your decision? Will you board the escape pod? Or will you not board the escape pod? If you wish to express remorse for his death, it is best that you survive. Otherwise, you will render his death meaningless."
  • Allen: "The two of us'll starve to death in this pod! You can't do this!"
    KOS-MOS: "Actually, suffocation would come first. Your air supply will be depleted in 46 hours."
  • "You are delaying me from my mission. I suggest you do as you please." (after Shion threatens suicide)
  • "Dish washing requires a rather fine adjustment of one's power output."
  • "I have confirmed that this object can be identified with a 99.99998% probability to be the Zohar emulator that was stored onboard the Woglinde."
  • "All photon, lepton, hadron, and graviton scans read negative."
  • "Shion... Will feeling pain... make me complete? Relinquish your pain unto me!"
  • "I am happy... to be of service."

Episode II

  • "Shion, if you interfere, I will be required to take drastic measures."

Episode III

  • "This is checkmate." (attacking Voyager)
  • "Shion, it appears that I have caused you undue emotional stress while my functions were suspended. I must apologize."
  • "Shion. Thank you. I know that I failed to protect you back then, but, this time... I will! I'm leaving the rest to you now, Shion!"
  • "The time we'll spend apart will be an instant in the flow of universal time. I know we'll meet again... so please don't be sad... Shion."





Xenosaga III KOS-MOS Oneshot Final Boss

KOS-MOS using D-TENERITAS to one-hit-kill Zarathustra.

  • D-TENERITAS, or "teneritas", is Latin for "softness" or "tenderness".
  • According to Soraya Saga, KOS-MOS's design was intended to reflect how she was the brainchild of Tetsuya Takahashi. Since human characters are often depicted as having a strong will in fragile bodies, KOS-MOS was the opposite, "being the delicate pieces of soul in an unbreakable vessel."[2]
  • When asked about voicing KOS-MOS, her English voice actress Bridget Hoffman said she admired her intellect and strength, as well as her "machine-ness" in comparison to the other roles Hoffman has played[3].

KOS-MOS Archetype.

  • In Episode I, KOS-MOS also has, like MOMO's Kirschwasser outfit, her Archetype. It is found in the A.G.W.S. Hangar in the Woglinde. This is only in the Reloaded version of the game, however.
  • In a trailer for Episode III, when Shion opens Mary Magdalene's coffin, she finds KOS-MOS.[6] In the final version, Shion finds Mary Magdalene.[7]
  • Xenosaga co-creator Soraya Saga has also stated that, along with Shion Uzuki, MOMO, Juli and Sakura Mizrahi, KOS-MOS's name is a reference to a flower. In KOS-MOS' case, it refers to the flower Cosmos bipinnatus, which are seen when Mary Magdalene appears in Episode III.

The infamous MOK-KOS.

  • The limited edition of Xenosaga Episode II includes an action figure of KOS-MOS. The action figure, called "Jashin MOK-KOS" by fans ("Jashin" stands for "evil god" in Japanese), spawned a meme.
  • Vector Industries developed a short-range weapon unit for KOS-MOS in secrecy known as the KWP-XI. It can be found in Episode III at the CAT Testing Ground once the Segment File is complete. It has 29 STR, 16 E ATK, 10 VIT and 10 DEF.

Cameos and references in other games[]

  • KOS-MOS' outfit, from her hair to her boots, is available as items for created characters in Soulcalibur III. It is known as the "Type X" outfit.
  • KOS-MOS' X-BUSTER appears in many Tales games, sometimes called Cross Buster.
  • In Tales of the World: Narikiri Dungeon 3, one can find an item that allows to make a KOS-MOS costume which allows her to be used in battle: interestingly, she is the only character not from a Tales game with a desperation move that requires low life to use, namely her X-BUSTER.
  • There is a KOS-MOS costume as Downloadable Content for the character Judith in the PS3 version of Tales of Vesperia.
  • KOS-MOS (Version I), as well as Shion Uzuki and MOMO, appear in Namco × Capcom, another game by Monolith Soft.[9]

Mugen no Frontier EXCEED KOS-MOS's All Attacks

KOS-MOS in Super Robot Taisen OG Saga: Endless Frontier Exceed.

  • She and T-elos also return in the sequel, Endless Frontier EXCEED, while this time also receiving support from MOMO.

Fiora and KOS-MOS / Mary Magdalene.

  • KOS-MOS's head armor from Xenosaga I makes a late game appearance in Tales of Arise as part of its artifacts system, where it is renamed as 'Mechanical Doll Accessory'. When on, it has the effect of making the party invisible to enemies. The description for it mentions that it would "look splendid with a floral companion" and that "[d]onning it brings about a respect for order". Both are references to KOS-MOS's name, while the former could alternately refer to Shion as well.
  1. Xenosaga: Official Design Materials, pg. 49.
  2. (2010, June 30). Soraya Saga On Xenogears And Xenosaga. Retrieved December 27, 2020, from https://www.siliconera.com/soraya-saga-on-xenogears-and-xenosaga/
  3. Bridget Hoffman at Matsuricon 2015. (2015, August 26). Retrieved December 27, 2020, from https://www.youtube.com/watch?v=j4vKlqQ7iMQ