KOS-MOS is a Rare Blade in Xenoblade Chronicles 2. She can grant tremendous power to her Drivers, Rex, Nia, Zeke or Mòrag, and their allies. KOS-MOS uses the light element, wields an Ether Cannon, and acts as an Attacker in battle. She is known as KOS-MOS Re: in the Japanese version.
KOS-MOS is a featured 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)
|Type||Name||Skill Level||Affinity Level||Effect||Prerequisite||Count||Flavor Text|
|Key Affinity Reward||1||1||Affinity Chart level 1 unlocked|
|2||2||Unlocks level 2 of the Affinity Chart||Increase Trust||100||"Expansion of main system functions is complete."|
|3||3||Unlocks level 3 of the Affinity Chart||Increase Trust||1,300||"Enhancement of main system functions is complete."|
|4||4||Unlocks level 4 of the Affinity Chart||Increase Trust||3,800||"Update of main system functions is complete."|
|5||5||Unlocks level 5 of the Affinity Chart. Affinity bond will be easier to sustain.||Go to the 7th Perimeter Skyport, World Tree and complete the quest "Artificial Intelligence".||"I offer thanks to you, Master."|
|Blade Special||R-Blade||1||1||Increases critical damage by 25%|
|2||2||Increases critical damage by 40%||Defeat a Wood Bunnit in Gormott||5||"Clean up complete. Battle systems enhanced."|
|3||3||Increases critical damage by 55%||Use R-Blade||11||"Battle systems enhanced."|
|4||4||Increases critical damage by 70%||Use R-Blade||12||"Battle systems enhanced. Firepower increased."|
|5||5||Increases critical damage by 85%||Use R-Blade||13||"Battle systems enhanced. Diagnostics indicate further expansion may be hazardous."|
|H-Effect R||1||1||When landing a hit, restores 30% of damage dealt to the whole party|
|2||2||When landing a hit, restores 35% of damage dealt to the whole party||Perform a Blade Combo||5||"Weapon systems enhanced. Enhancements are available in future battles."|
|3||3||When landing a hit, restores 40% of damage dealt to the whole party||Use H-Effect R||8||"Weapon systems enhanced. Battlefield capabilities improved."|
|4||4||When landing a hit, restores 45% of damage dealt to the whole party||Use H-Effect R||9||"Weapon systems enhanced. Mobility systems have been optimized."|
|5||5||When landing a hit, restores 50% of damage dealt to the whole party||Finish an enemy||40||"Weapon systems enhanced. Diagnostics indicate further enhancement may be hazardous."|
|F-G-Shot||1||1||Adds a 60% chance of dealing a guard-annulling attack|
|2||2||Adds a 70% chance of dealing a guard-annulling attack||Use F-G-Shot||5||"Ether conversion rate increased. Output has been significantly boosted."|
|3||3||Adds a 80% chance of dealing a guard-annulling attack||Perform a Driver Combo (It's enough to just be present)||7||"Locked on to leader's movements. Strategic capabilities will be enhanced in subsequent battles."|
|4||4||Adds a 90% chance of dealing a guard-annulling attack||Use F-G-Shot||7||"Ether conversion rate increased. Battlefield capabilities improved."|
|5||5||Adds a 100% chance of dealing a guard-annulling attack||Defeat a Gerolf Sovereign at the World Tree||4||"Ether conversion rate increased. Diagnostics indicate that further increase would be hazardous."|
|Battle Skill||Phase Transition Tech||1||1||Annuls enemy defense and increases Special damage dealt by 60%|
|2||2||Annuls enemy defense and increases Special damage dealt by 70%||Perform a Blade Combo||5||"Support mode is fully operational."|
|3||3||Annuls enemy defense and increases Special damage dealt by 80%||Perform a Blade Combo||7||"Support systems enhanced."|
|4||4||Annuls enemy defense and increases Special damage dealt by 90%||Perform a Blade Combo||10||"Master, I hope you are satisfied with my performance."|
|5||5||Annuls enemy defense and increases Special damage dealt by 100%||Perform a Blade Combo||12||"Threats met with maximal force."|
|Hyperclock||1||1||Deal 60% more and take 10% less damage at max Affinity||Perform a Blade Combo||2||"Master, a report. New power is ready to deploy on your mark."|
|2||2||Deal 70% more and take 15% less damage at max Affinity||Use KOS-MOS's favorite pouch items (Board Games category)||2||"Thank you, Master."|
|3||3||Deal 80% more and take 20% less damage at max Affinity||At a place in the First Low Orbit Station with a view of the outside, view the Heart-to-Heart "Daybreak"||"Databanks enhanced with new input from Master-Blade conversation."|
|4||4||Deal 90% more and take 25% less damage at max Affinity||Raise Affinity in combat||6||"Analysis systems expanded. Battlefield contribution has been significantly increased."|
|5||5||Deal 100% more and take 30% less damage at max Affinity||Raise Affinity in combat||7||"I will deploy all available resources to support your attack, Master."|
|Encephalon||1||1||Reduces aggro build-up from attacks by 20%|
|2||2||Reduces aggro build-up from attacks by 25%||Perform a Driver Combo (It's enough to just be present)||5||"Superb movement, Master."|
|3||3||Reduces aggro build-up from attacks by 30%||Perform a Driver Combo (It's enough to just be present)||7||"Would you like me to display the results of my strategic simulation?"|
|4||4||Reduces aggro build-up from attacks by 35%||Perform a Driver Combo (It's enough to just be present)||10||"Master. Please remember that you can count on my support."|
|5||5||Reduces aggro build-up from attacks by 40%||Perform a Driver Combo (It's enough to just be present)||12||"Master! I will participate in your assaults."|
|Field Skill||Light Mastery||1||1||The power of a Light Blade.|
|2||3||Defeat a Spanner Bunnit in Mor Ardain||5||"Output increased. Significantly more power resources became available."|
|3||4||Defeat a Gerolf Sovereign at the World Tree||4||"Master, output has increased to the maximal possible value."|
|Lockpicking||1||1||The power to open various things. Works on doors, treasure troves, etc.|
|2||3||Collect stuff||7||"New analysis subroutines became available."|
|3||4||Collect stuff||7||"High-level analysis subroutines became available."|
|Mental Arithmetic||1||1||Perform complex calculations at speed. Skill exclusive to KOS-MOS|
|2||3||Use a Special||11||"Update complete."|
|3||5||Use a Special||15||"Enemy annihilation complete."|
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.
- The Pink blades around KOS-MOS are known as a "Gravity Shell" and, according to his Production Note, were added by Kunihiko Tanaka to make her more like a magical girl.
Following Pyra and Mythra figures by Good Smile Company, and Siren by Kotobukiya, a KOS-MOS figure made into a 1/7 scale by Good Smile Company and based on her design from Xenoblade Chronicles 2 was announced on July 29th, 2018.