Bridget Hoffman (I, III) Colleen O'Shaughnessey (II) Luci Christian (anime)
I am happy... to be of service.
—KOS-MOS, upon attempting to sacrifice herself to save the Elsa.
Shion. There is a 99.99998% probability that this is the Zohar Emulator stored on board the Woginde
KOS-MOS is an armored gynoid, developed by the interstellar conglomerate Vector Industries. She is comprised of entirely mechanical parts (possibly from a superior breed of complex nanomachines), a rarity in the age of advanced Realian technology. The basic tenet to which she adheres is based on logic, probability, and completion of her mission above all else. She also unconditionally protects Shion Uzuki, her co-creator. She is equipped with a "Simulated Personality OS" to aid in communication, and though her speech conveys her role as an gynoid 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 recursive acronym used to denote an anti-Gnosis tactic system. It stands for "Kosmos Obey Strategical Multiple Operation Systems". Her development name is "KP-X", and she is self classified as a "Special Humanoid Anti-Gnosis Annihilation Weapon". Her serial number is "00-00-00-00-1". She appears to be emotionless, but throughout the series, evidence indicates that this is not entirely true.
KOS-MOS has significant powers believed to be superior to all other party members. 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. She also possesses the ability to summon weapons such as the F-GSHOT chainguns and her famous F-SCYTHE and equipment either from some internal chamber that compresses space or from another location via teleportation. She also has a long-range sensory array, the D.S.S.S. system and CPU that either rivals or exceeds even those possessed by Observational Realians.
She also possesses the Hilbert Effect but its power is easily thousands of times greater than that achieved by even the largest spaceships.
In Episode 1, KOS-MOS also has, like MOMO's Kirschwasseroutfit, her Archetype.
You can get it in The Woglinde. When in this area, proceed to the AGWS Hangar. Search around this Hangar, and then you should be able to find and unlock the Archetype KOS-MOS outfit. This is only in the Reloaded version of the game, however.
KOS-MOS possesses several black box components left behind by Kevin Winnicot 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.
KOS-MOS has one last weapon system called the Tertiary Weapon System, which is seen periodically throughout the series. They consist of a set of energy wings, a pair of energy cannons and other attachments meant to be fitted onto her. The wings and cannons are part of a Phase Transfer Cannon. 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. The exchange that follows destroys several galaxies. The "Third Armament" as its 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 Phase Transfer blast by Proto Omega.
An almost human alternate persona tends to come out from time to time 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. Therefore, this version of KOS-MOS plays the role of Shion's guardian.
Blue-eyed KOS-MOS has made three appearances in Xenosaga so far: wiping out a fleet of Gnosis surrounding the Cathedral Ship with her X-Buster attack, saving the Elsa from burning up in the Second Miltian atmosphere, and saving Shion and Allen from being killed by Voyager, the Black Testament. 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. Shion has not directly seen KOS-MOS in her blue-eyed form and is oblivious to this second persona's existence until Episode III.
Xenosaga's final chapter, Episode III: Also Sprach Zarathustra saw the final developments of the character as the true purpose of her design finally became apparent. In Episode-III 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 expendible asset, she is used as a live-fire opponent for the new Omega 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 however to have some effect as Omega malfunctions during the fight, and it is forced to cancellation.
When T-elos is demonstrated as being superior, KOS-MOS is ditched in a garbage compacter. There she is found and reactivated by Shion, and company. KOS-MOS continues to travel with the group until doing battle with T-elos in Rennes-la-Chateau. The two engage in a pitched battle, in which 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 a woman dressed in humble clothing as she stares at T-elos.
When KOS-MOS is examined by Shion, Allen and the Professor, 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 Winicott (unknown to him) while masquerading as U-TIC personnel. Then with the assistance of the professors Erde Kaiser technology KOS-MOS is rebuilt into her Version-IV form. The new KOS-MOS is considerably more powerful, and awakes 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 Winicott, something she was incapable of beforehand.
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. 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. (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 (it means she got Mary Magdalene's memory and power). After the group defeats Kevin the Red Testament they enter the chamber of Zarathustra. 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, and stating that her name is not Mary, but KOS-MOS with her eyes red instead of blue previously. It is left to interpretation if KOS-MOS and Mary are two separate entity or if KOS-MOS is the result of the merging of Mary's consciousness and her original OS.
A violent battle then ensues as Zarathustra goes out of control. 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.
The group then retreats, and KOS-MOS begins fighting the many Gnosis who attempt to attack Chaos and Nephilim. Beforehand KOS-MOS transfers a part of Mary to Nephilim. (It is not clear within the confines of what is shown if she transfers the spirit of Mary, or merely the animus power) 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 however they are attack 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 however as this buys Chaos and Nephilim the time to finish.
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 in her head telling her that apparently the universe still needs them. He then tells KOS-MOS to sleep until they are needed again. The final scene is of KOS-MOS closing her eyes, as she drifts through space toward the sun rising over Earth.
The limited edition of Xenosaga: Episode II includes an action figure of KOS-MOS. The action figure is called "Jashin MOK-KOS" ("Jashin" stands for "evil god" in Japanese), because its shape is terribly ugly.
Nearly every element of KOS-MOS' outfit, from her hair to her boots, is available as items for created characters in Soul Calibur III (Known as the "Type X" outfit). One might say she made a cameo in that game, because if you use each piece of Type X clothing with original colors, KOS-MOS is created.
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.
In Tales of the Abyss, the character Anise can use X-BUSTER with the help of a rare item.
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 x Capcom, another game by Monolith Soft.
KOS-MOS, in her version IV form, along with T-elos also appears in the role-playing game called Super Robot Taisen OG Saga: Endless Frontier. Her capsule is discovered in the basement of a castle, which had been recovered after it was brought into the Endless Frontier. When the main character's party finds the capsule and opens it, KOS-MOS activates, noting that the final checks on her new form were not yet complete. KOS-MOS also recognizes two members of the party, Reiji Arisu and the kitsune Xiaomu, from the events of Namco x Capcom, putting the two games in continuity with each other. T-elos also appears as an enemy in the game, though their conflict (hinted but not explicitly said to be the events of Episode III) remains unresolved by the end, where they are presumed to have returned to their home dimension. She and T-elos have also been confirmed to return in the sequel, Endless Frontier EXCEED, while this time also receiving support from MOMO. T-elos appears as an enemy, but at some point in the game joins the party as a support character as well. Both games also feature the two main characters from Namco x Capcom, whom KOS-MOS recognises, placing the two series' in continuity with each other.
KOS-MOS also appears in Project X Zone, also by Monolith Soft, alongside T-ELOS. Haken Browning and Kaguya Nambu from the Endless Frontier series also make an appearance, as well as Reiji and Xiaomu.