KOS-MOS is a character based on KOS-MOS from the Xenosaga series. She is an armored android robot combat weapon with an artificial intelligence. Her design is based on the KOS-MOS's Version 1 model from Xenosaga Episode I: Der Wille zur Macht; both the original and redesign are by Kunihiko Tanaka. Her cannons' design resembles the Zohar.
- Lvl.1 - R-Blade - Puts enemies into a hornet's nest by spraying out bullets.
- Lvl.2 - H-Effect R - Develop the Hilbert Effect and change the course of battle.
- Lvl.3 - F-G-Shot - After charging energy, shoot out scattered laser beams.
- Lvl.4 - X-Buster - Fire a concentrated laser beam, but only when energy reserves are full.
- Recharge Boost - Boosts Arts recharge from auto-attack.
- Arts Plus - Boosts power of next Driver Art.
- Critical Up - Increases critical hit rate.
- Phase Transition Tech - Annuls enemy defense and increases Special damage dealt.
- Hyperclock - Deal more damage and take less damage at max affinity.
- Encephalon - Reduces aggro build-up from attacks.
- Light Mastery - Lvl. 3
- Lockpicking - Lvl. 3
- Mental Arithmetic - Lvl. 3 (Skill exclusive to KOS-MOS)
- Pouch item types: Staple Foods, Board Games
- Pouch items: Master's Curry (Staple Foods), Gladiator Wrestling (Board Games)
Some point after awakening her, she will start the quest Artificial Intelligence.
- KOS-MOS from the Xenosaga series has most of the time red eyes, and blue eyes at the times when her original persona (Mary Magdalene) is awake. But, in Xenoblade Chronicles 2 she has apparently pink eyes.