Koyanskaya of Light is summoned as a Servant of Chaldea Security Organization after the events of the Tunguska Special Territory incident. She is one of two fragments that spilled out from Lostbelt: Beast IV's sealed cage: the side of her that respects humanity and has a soft spot for humans - just a little - compared to when she was Chaldea's enemy.
When displaying her divinity in her Third Ascension, she refers to herself as Tamamo Vitch Koyanskaya Weapon (タマモヴィッチ・コヤンスカヤ・ウェポン?), the Greater Goddess of Weaponry Ikusautsuwa-no-Oomikami (戦器の大御神?), as she homages the culture that originated Tamamo-no-Mae.
A captivating beauty who bewitchingly leads humans around by the nose, following her policies of free and uncontrolled wildness. She regards all human activity as filthy, but that doesn't mean she dislikes any of it. Some things are only fun because they're dirty. Indeed, entertainment, games, business.
As you can see, due to her personality demanding her to enjoy everything she does, her attacks on humanity are very roundabout. After considering many possible ways to dunk on humanity, she reached a conclusion: "Perhaps keeping them under their treasured pet's management and gradually degrading them is my most humiliating and most perverse option." And so she chose to trail the path of a goddess of weaponry, what humanity deserves to be ruled by.
- Independent Manifestation (Rank C): The proof that she's a SPY. Drifter abilities. Due to her Beast traits, Koyanskaya can visit any alternative world or alternative reality. When Koyanskaya was a Beast in the making, she could use this Skill to freely move between Lostbelts and the blank Earth, but due to the big rank down on this Skill, she can't move as freely as she previously could.
- Independent Action (Rank EX): Surprisingly and terrifyingly enough, Light Koyanskaya doesn't need a Master. She abides by her Master's Command Spell for a single reason. Only her pride telling she'll never break a promise or contract.
- Shapeshift (Rank A): This was originally a Skill to raise defense, but Koyanskaya uses it as her favorite tool for SPY activity.
- Goddess Metamorphosis (Guns) (Rank B)
- Aptitude for Slaughter (Man) (Rank A): A variation of a personal Skill of Archimedes, the founder of mathematics. Archimedes accidentally created massacre weapons that surpassed the state-of-the-art weaponry of his time, but Koyanskaya gained this Skill on purpose.
The Skill allows her to use any weapon used by humanity from the era she's in, and the weapons become multiple times more powerful than they were in human hands and able to instantly perform the natural cycle of retributive justice (karma normally takes it slow, occurring liberally through the span of a few centuries). Fitting for a former Beast in the making, this Skills represents the fact that, on paper, humanity doesn't stand a chance against her in this era. That said, this Skill serves only to assert dominance on humanity, so it's not nearly that absolute of a Skill against Servants or Monsters.
- Innovator Bunny (Rank A): The Authority to improve profit-making systems and creates cycles dedicated solely to tormenting (exploiting) humans... or so she claims with the smuggest shit-eating grin on her face. It's actually just a hobby and a talent of hers.
- NFF Special (Rank A): No information available.
Koyanskaya of Light is illustrated by Arco Wada. She was first introduced as a Servant on March 31, 2018 during the commercials leading up to the release of the first story chapter of Part 2 of Fate/Grand Order. She was implemented August 1, 2021, the last of the eight Servants to be released.