KOS-MOS, developed by Kevin Winnicot, KOS-MOS was designed to be the premier Anti-Gnosis weapon. During a rather tragic incident, where KOS-MOS awakened prematurely, she killed Kevin and most of the development team. Shion Uzuki was one of the only survivors at the incident. With Kevin dead, Shion was promoted to Chief Engineer of the KOS-MOS Project General Operation System research Centre, Vector Industries R&D Division.

KOS-MOS continued to be outfitted and tested, but the core remained the same as in the archetype. This lead to the division spending a great deal of time collecting data to determine what was in her black box.

KOS-MOS possesses several black box components left behind by Kevin Winnicot. Each of these black box features are found in each of her skeletons, version 1, version 2, version 3, and version 4. One of these is her potent X-BUSTER weapon, a powerful burst of energy beams from her abdomen that absorb the Gnosis. Others are related to her "simulated personality" OS and her self-awareness which is more in fact Mary Magdalene resting inside of her. KOS-MOS also has some form of energy manipulation tied to the Zohar. The Red Testament, Kevin Winnicot, claimed that KOS-MOS's power came from "U-DO using the Zohar as a door".

When Planet Ariadne vanished, the Woglinde was sent by Vector to investigate. As a precaution against Gnosis attack, the KOS-MOS project was taken as well. Though not fully combat ready, KOS-MOS self-started to protect Shion when the Gnosis attacked. During the travels that followed, KOS-MOS' combat capabilities were fully realized.

Some noticed that at times KOS-MOS' eyes turned blue and she spoke very differently. On these occasions, her power level became much greater, but they never lasted long. The one person most experienced with KOS-MOS, Shion, has yet to see this transformation.

KOS-MOS' actions are dictated by logic and a list of directives. She follows these with precision and lethality (as was seen when she killed Lt. Virgil when he would have lowered her abilities). Some of her directives are a mystery, even to Shion.

An almost human alternate persona tends to come out from time to time in the form of a blue-eyed KOS-MOS. This blue-eyed KOS-MOS is far more powerful than red-eyed KOS-MOS and talks in a more human-sounding voice.

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. Her 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.