Koyanskaya of Light

“Think of me as simply a hypercompetent sexy secretary bunny!”

Koyanskaya always loves to shake everything up if it ends with her reaping profits in some way. So what else would be better than taking thousands upon thousands of NA Master’s Saint Quartz to create an entirely new meta? As one of the premiere Buster Support Servants, and also the first major support Servant capable of casting a Buster AoE Damage Noble Phantasm, she is one of the top Servants available in the game.

Koyanskaya will change the game by allowing Buster Noble Phantasm looping. This all is made possible by Innovator Bunny, which gives both a charge and a skill cooldown reduction. Even without her looping support, she also provides major Buster damage support with NFF Special A and further gives support to a niche with Massacring Technique (Human) A.. As if that wasn’t enough, she is a decent damage dealer herself with her Noble Phantasm, Iz Tula Seven Drive.

The biggest drawback of Koyanskaya is her total lack of defense. Not only does she lack any skills to mitigate damage or heal damage, but Innovator Bunny actually deals damage to the party. Koyanskaya also is far less versatile of a Servant than the earlier meta-breaking Servants such as Skadi and Caster Altria, and can only be successfully deployed in Buster teams.

Koyanskaya is a crucial Servant for any Buster team, ultimately changing the game as we know it. Not to mention, she is the queen of all that is fluffy in the world!

Buster Looping Support

Koyanskaya’s first skill charges a NP Gauge by 50% and decreases cooldowns by 2 turns. This can effectively be used to give any Servant with a 50% self-charge on a 7-turn or less cooldown the ability to cast 3 Noble Phantasms in 3 turns with the Atlas Academy Mystic Code and a Kaleidoscope. The Servant begins with 100% charge using either a MLB Kaleidoscope (or a non-MLB with max append 2 skill). Turn 2, the Servant uses their self-charge 50% skill and one of Koyanskaya’s charges. Then turn 3, they use a support Koyan’s charge and Atlas Academy’s cooldown reduction to get their own charge off cooldown and fire again. Unlike previous looping compositions, this will work independent of enemy composition. 

Buster Damage Support

Koyan’s third skill gives a Servant a massive boost to their Buster damage for 3-turns, filling out the triangle with Skadi and Caster Altria for Quick and Arts respectively. She also provides allies with large Buster Crit buffs for the rare cases where a Noble Phantasm isn’t enough damage alone. On top of this, her second skill gives even more damage against Human attribute + trait enemies, which consist of about a third of the enemies in the game. 

AoE Damage

Unlike other supports, Koyanskaya is capable of dishing out NP damage on her own. Her Noble Phantasm more than rids herself of her 0.9x Assassin class modifier with its 20% attack up buff, and it is further buffed with an insane passive of Goddess Metamorphosis (Guns) giving 20% NP damage up permanently. She has one of the hardest hitting Noble Phantasms among all AoE Assassins, and with a second Koyanskaya, Oberon, and a 50% split charger such as Reines or Waver, can also loop.

Squishy

Koyanskaya has no defensive skills, no hard counters, and a relatively average health pool for a 5-star Servant. If an enemy is about to use a Noble Phantasm, she will not survive without outside support. Not to mention to use her charge, she has to take 1000 damage along with everyone else in the party.

Niche

Koyanskaya has a powerful Buster buff and can boost damage against human attribute / trait enemies, but that is the extent of her damage support. Unlike other major supports, she lacks a Charisma or a Defense down, meaning that she cannot be paired as effectively with non-Buster Servants. This also means that her damage support in general will be less than most Arts or Quick compositions. These damage issues however are largely addressed when considering a certain mothman in the equation…

Koyanskaya’s skills are designed to enable looping by Buster Servants. By using her first skill to both charge 50% gauge and reduce cooldown by 2 turns, she creates situations where Servants can cast 3 Noble Phantasms by using their own self-charge skills twice. Her other skills are pure long-term damage boosts. Masters will pretty much always use her second and third skills on turn one to boost damage for the node, and her first skill on turn two to reduce cooldowns and create another Noble Phantasm.

• Innovator A is a massively useful skill that provides both up to 50% NP gauge and reduces cooldown by 2 turns. When another Servant has a 7-turn or less cooldown, two of these casts will reduce it to 3-turns (using a support), Atlas Academy will reduce it to 1 turn, and wave 3 will take it off cooldown. Once a certain mothman comes along, this further will enable looping from any Servant with a 30% charge on a 6-turn or less cooldown. This skill’s charge is crucial for all looping compositions, so should be leveled first to max. Unfortunately, it is on an 8-turn cooldown so it can’t be used twice by any one Koyanskaya herself. 
• Massacring Technique (Human) A primarily serves to create a niche against about a third of all enemies. The “Human” attribute typically applies to Servants who were real life humans as opposed to legends or gods, but there are exceptions. “Human” trait is primarily meant for enemies like zombies and soldiers instead of Servants, who typically have low HP to begin with. This trait is typically just ignored. It also works quite well with her third skill to provide a bunch of stars, so Masters may want to just hold off on using this skill until they need the star bomb. This also gives a small NP gauge charge on Buster cards, although this may not see as much usage as other traits in looping scenarios. This skill should be leveled last and can be left at 9 if necessary, but is better at 10 for if Koyanskaya is doing the damage herself to give 2 star bombs. 
• NFF Special A grants one ally a huge boost to Buster damage, critical damage, and critical star gather rate. This is what turns her from a support to a super-support. Not only that, it is on a 6-turn cooldown, meaning if Koyanskaya herself is doing the looping with a certain Mothman as support, she can cast it twice for a large damage boost on wave 3. 

Koyanskaya’s Craft Essences depend on whether she is supporting or doing the looping herself. If she is serving as a support, she works really well with Bond CEs / Event Bonus CEs to give everyone a little extra currency at the end of the node. If she is being used for damage, she needs a 50% charge CE, with Mixed Starting Gauge / NP Damage CEs being optimal. Pure NP Damage CEs are decent if planning to only use her for two Noble Phantasms with supports. Any other 50% Charge CEs will allow her to loop with less damage.

• Chaldea Lunchtime / Chaldea Teatime / Great Detective Foulmes / Cosmo Chaldea High School: When supporting, there will almost always be enough damage to not need any further boosts from Koyanskaya. So she is best putting on a bond CE for farming to get the Bond 6+ bonus Saint Quartz, or something to boost event drops. The event bonus CE obviously depends on the event, but Cosmo Chaldea High School is used as a sample because it has Helena who is an awesome servant you should love and worship as your goddess (note: no author bias, promise). 
• Holy Night Supper / Aerial Drive: When looping her own Noble Phantasm, Koyanskaya requires Oberon. So NP damage is far better than any other combinations of 50% charge CEs by far. 
• The Black Grail: Koyanskaya can take advantage of damage increases from The Black Grail in situations where her Noble Phantasm is only required one or two times. She is powerful enough as a Servant for it to work.
• Golden Sumo: Boulder Tournament / Partake with the King / Starry Nights / Dragon’s Meridian: Any 50% starting gauge CE will enable self-looping with the right supports, but to far less effect than CEs with both a starting gauge and NP damage up effects.