Rabbit's Reviews #315: Koyanskaya of Darkness (5* Foreigner)

Introduction

Foreigners are basically wannabe Avengers. Like Avengers, they’re neutral to basically everything, although they lose out on class advantage against Rulers in exchange for resistance to Berserkers. This isn’t bad in theory, and Avengers tend to be among the best Servants in the game… but sadly, Foreigners don’t get the same love, by and large. Avengers get all kinds of fantastic innate bonuses that help make up for their lack of meaningful class advantage—super high attack, an innate damage modifier, great passives, et cetera—but Foreigners are not nearly as inherently advantaged. With one key exception (which I’ll address later), nothing in Foreigners’ bases make them substantially more appealing than any other given class, so they need really amazing kits in order to let them outshine the better Extra classes or Servants with class advantage.

Sadly, Koyanskaya of Darkness does not do that. While she has quite a bit of utility within her kit, at the end of the day, she’s a DPS, and as a DPS she doesn’t do enough to outweigh being in a generally weak class. Her kit is somewhat similar to Jiang Ziya’s, actually, in that she brings enough party utility to serve as a plausibly strong semi-support… but she is weaker in two important ways: first, her support value is only notable when supporting a very small group of Servants, and second, Buster has a broader array of valuable SSR supports than Quick does, which means players are less likely to need a semi-support, and less likely to have space in a team to slot her in, even within her own niche. As such, despite her splashable buffs, she’s primarily a damage-dealer. As a damage-dealer, though, she has good-but-unremarkable buffs and some neat niche utility. In exchange for this, she has bad cooldowns, weak synergy with her best support, situational damage output, and, of course, essentially no class advantage context. She’s a situational investment at best and not even especially valuable in those cases.

Servant Data

Foreigner

QAABB (Saber)

Quick Card

Arts Card

Buster Card

4

3

5

Attribute	Beast
Alignment	Chaotic Evil

Stage 1
Stage 2
Stage 3
Stage 4

April Fool's

Max HP 14,700

HP Rank

Max ATK 11,220

ATK Rank

Base Atk	1,734	Base HP	2,156
Max Atk	11,220	Max HP	14,700
Grail Atk	12,282	Grail HP	16,104

Entity of the Outer Realm C

Gain 2 Critical Stars per turn.
Increase your Debuff Resist by 6%.

NFF Services EX

Apply 20% Special ATK [Wild Beast] to self.
Increase own Arts Card effectiveness by 5%.
Increase own Debuff Success Rate by 10%.

Nega Self C

20% Chance to inflict Nullify Buff (1 time, 3 turns) on [Wild Beast] enemies when attacking.

Card Hits	4	3	3	5	5
Per Hit	0.67%	0.67%	0.67%	0.67%	0.67%

	NP per Hit (%)						0.67%
	NP when Attacked (%)						3%

	Star Absorption	153
	Star Generation per Hit	14.8%

Overview

Koyan has middling stats for a Foreigner, with mid-low attack and mid-high HP. This isn’t a great starting point for a DPS, but at least she’s not Voyager (sorry Voyager). Foreigners are usually pretty good at star gen, but Koyan only has one Quick and her hit-counts aren’t abnormally high, so her star gen will feel more typical for her deck than for her class. Her NP gain, similarly, is a little better than average for her deck, though not substantially so.

For passives, Koyan gets the Foreigner-standard Entity of the Outer Realm, for some extra star gen and, more importantly, Van Gogh compatibility. This is the Foreigner advantage I alluded to above—Foreigners benefit from Van Gogh’s massive crit buffs, and Koyan in particular is a great component of Van Gogh teams specifically. Koyan’s other two passives are unique to her. NFF Service boosts Koyan’s damage against Wild Beast enemies, which only includes eight Servants at the time of writing but at least counts a decent number of generic mobs. NFF Service also boosts Koyan’s Arts performance a touch, helping her NP gain, and makes her debuffs more likely to land, which helps her consistency. Koyan’s final passive, Nega-Self, gives her a 20% chance to inflict buff block against Wild Beast enemies with her attacks. This is a 30% chance in practice, as NFF Service’s boost applies here, and unlike most effects of its type, it also applies to Koyan’s NP. Again, Wild Beast is a fairly limited niche, especially when you’re looking specifically at hard fights, but this does make Koyan something of a silver bullet for the small subset of fights where this passive applies.

For appends, Mana Loading is far and away the most important. Since Koyan has a 30% battery, she requires Mana Loading in order to loop reliably with Koyan/Koyan/Oberon and a 50% starting charge CE. Mana Loading is great in general and well-worth the investment. Koyan’s Extra Attack buff, meanwhile, is useful if you plan to use her in crit-focused teams, but otherwise it’s not a huge buff. Koyan’s specialty damage append gives damage versus Rulers, turning her into a pseudo-Avenger for the purposes of Ruler-killing. This is decent if you don’t have a favored Avenger, but given how accessible Salieri and Ranmaru are, this is probably not worth the coins.

Material Requirements

Stage	Cost	Materials
2	100,000	x10 Void's Dust x10 Fool's Chain
3	300,000	x10 Phoenix Feather x10 Black Beast Grease
4	1,000,000	x10 Claw of Chaos x10 Primordial Lanugo
Max	3,000,000	x10 Tearstone of Blood x10 Fragment of a Twinkling Star

Level	Cost	Materials
1 → 2	200,000	x10 Proof of Hero
2 → 3	400,000	x10 Evil Bone
3 → 4	1,200,000	x12 Homunculus Baby
4 → 5	1,600,000	x12 Mystic Spinal Fluid
5 → 6	4,000,000	x12 Giant's Ring
6 → 7	5,000,000	x15 Reactor Core of Dawn
7 → 8	10,000,000	x15 Tsukumo Mirror
8 → 9	12,000,000	x15 Fragment of a Twinkling Star
9 → 10	20,000,000	x1 Crystallized Lore

Level	Cost	Materials
1 → 2	200000	x10 Deadly Poisonous Needle
2 → 3	400000	x10 Claw of Chaos
3 → 4	1200000	x12 Black Beast Grease
4 → 5	1600000	x12 Primordial Lanugo
5 → 6	4000000	x12 Cursed Beast Gallstone
6 → 7	5000000	x15 Mysterious Divine Wine
7 → 8	10000000	x15 Vision Scales
8 → 9	12000000	x15 Egg of Truth
9 → 10	20000000	x1 Crystallized Lore

Servant Skills

Koyan is an example of a Servant with a remarkably busy skillset that still manages to not actually do a whole lot. Recommended skill order is 1>2>3.

Buster Up

Dominator Fox A

Increase Buster Card effectiveness for all allies (3 turns).
Increase NP Gauge for all allies.
Decrease Critical Star Gather Rate by 100% for all [Hominidae Servant] allies (1 turn).

Show Info

Lvl	1	2	3	4	5	6	7	8	9	10
Buster +	20%	21%	22%	23%	24%	25%	26%	27%	28%	30%
NP +	20%	21%	22%	23%	24%	25%	26%	27%	28%	30%
CD	8	8	8	8	8	7	7	7	7	6

Dominator Fox is a good skill, and it would be a great skill on another Servant. Pairing an AoE 30% Buster buff with a fantastic AoE 30% battery, this skill calls to mind Castoria’s first skill. If Koyan’s kit followed through on its promise, this would set her up to be a fantastic support. As it is, though, this mostly functions as a self-battery that also helps to get supports access to their NPs. Unfortunately for Koyan, most of her preferred supports don’t have particularly good NPs. The 6-turn cooldown at max level also means it takes longer for Koyan to stack this skill with double Koyanskaya of Light than a typical 30% buff would. It’s a bit odd—the primary effects of this skill make for a fantastic skill in a vacuum, but they’re on a Servant who struggles to make good use of them. The skill also reduces star weight of Hominidae Servants for a turn, further reinforcing Koyan’s intended DPS role—this skill helps Koyan crit but, conversely, will generally make it harder for allies to crit. Furthermore, even if Koyan is supporting Wild Beast Servants, this skill doesn’t suppress Koyan’s own Archer-esque star weight, limiting its usefulness. To add insult to injury, Koyan’s best support, Koyanskaya of Light, is not Hominidae, which limits this skill’s ability to help Koyan crit even when Koyan is used as a DPS. Despite all this, the skill is at least truly fantastic for Van Gogh teams, helping all three Servants NP more reliably and boosting their Buster crits… but outside of those teams, it’s a surprisingly awkward skill.

Overcharge Up

Massacring Beasts A

Increase NP Overcharge level by 2 for an ally (1 time, 3 turns).
Apply effect on an ally (3 turns): When attacking with Buster Cards, gain 5 Critical Stars.
Increase ATK and DEF for all [Kemono] trait allies (3 turns).

Show Info

Lvl	1	2	3	4	5	6	7	8	9	10
ATK +	20%	21%	22%	23%	24%	25%	26%	27%	28%	30%
DEF +	20%	21%	22%	23%	24%	25%	26%	27%	28%	30%
CD	9	9	9	9	9	8	8	8	8	7

Beasts of Slaughter would be an okay skill on a shorter cooldown. It does a couple of things—on the less-impactful side, it boosts an ally’s overcharge level and makes their Buster cards generate some stars. These effects conflict a little bit. You might want to give the Overcharge buff to someone like Merlin or Castoria, who can use it well, but they only have one Buster each and don’t typically want to use them, so the star gen effect is wasted. Conversely, if Koyan is supporting a DPS who might prioritize Buster cards, that DPS won’t necessarily have an Overcharge worth boosting. The pool of Buster Servants who have the Kemono trait and good Overcharge effects is pretty small—I count 12, being generous and including certain post-damage benefits as well—which limits Koyan’s ability to make full use of this skill in a supportive context. This naturally leads to the other two effects: attack and defense up for Kemono Servants. Supportively, this is a decent buff, increasing damage and tankiness for a small pool of allies. For Buster Servants with this niche, Koyan provides roughly the same level of buff value as Tamamo for Arts or Jiang Ziya for Quick, provided she can access her NP. Unfortunately for Koyan in this comparison, the other two have no niche requirements, and Arts and Quick teams are lacking more appealing alternatives, while support Koyan has to compete with Merlin, who does similar things more effectively even within Koyan’s niche. The long and short of this is that the skill has a lot of potential supportive value, but that value isn’t strong enough to really merit how limited and specific the skill is. That said, Koyan herself benefits fully from this skill, with the ability to leverage every aspect of it effectively. For a support Koyan, this is an iffy skill, but for a DPS Koyan, it’s a solid offense and survivability buff… until you consider the cooldown. This skill is on a 7-turn CD, which means Koyanskaya of Light teams don’t allow it to stack with itself. The skill is not powerful enough to merit its long cooldown, and this skill’s inability to self-stack really hurts Koyan’s damage potential relative to other Buster AoEs in practice. With a few tweaks, this could be a good skill, but as it is it’s honestly pretty bad.

Shield Break

Goddess Morph (Beast) B

Apply Ignore Invincible to self (3 turns).
Increase own Critical Strength (3 turns).
Apply effect to self (3 turns): When attacking an enemy:
- Inflict Poison on the target (3 turns).
- Inflict Curse on the target (3 turns).
- Inflict Burn on the target (3 turns).
Apply Poison Damage Up on all enemies (3 turns).
Apply Curse Damage Up on all enemies (3 turns).
Apply Burn Damage Up on all enemies (3 turns).

Show Info

Lvl	1	2	3	4	5	6	7	8	9	10
Crit Damage +	30%	32%	34%	36%	38%	40%	42%	44%	46%	50%
Poison Damage +	300	320	340	360	380	400	420	440	460	500
Curse Damage +	300	320	340	360	380	400	420	440	460	500
Burn Damage +	300	320	340	360	380	400	420	440	460	500
Poison Damage Up	50%	55%	60%	65%	70%	75%	80%	85%	90%	100%
Curse Damage Up	50%	55%	60%	65%	70%	75%	80%	85%	90%	100%
Burn Damage Up	50%	55%	60%	65%	70%	75%	80%	85%	90%	100%
CD	8	8	8	8	8	7	7	7	7	6

Goddess Morph has way more text than its practical complexity should warrant. It’s basically just a utility skill that also boosts card damage. Three-turn pierce invuln is a great effect on a DPS and can simplify a lot of annoying fights. The skill then provides a decent crit damage buff, which would be good if Koyan had easier crit access. As it is, though, Koyan is highly dependent on supports for crit enabling, which makes the crit damage buff feel a little out of place. After that, the skill doubles the effect of all three major damage-over-time effects and lets Koyan’s cards inflict Poison, Curse, and Burn all at once. In sum, this means each of Koyan’s cards adds an extra 3000 per turn in damage-over-time for three turns. This can add up to substantial extra damage, but it doesn’t scale with any convention support buffs, which limits its value in practice. All-in-all, this skill is fine. It would be a respectable filler skill on a better DPS, but unfortunately it doesn’t do enough to tie together Koyan’s kit.

Noble Phantasm

Tunguska Nine Drive C

Increase own ATK by 20% (1 turn) [Activates first].
Deal damage to all enemies.
Remove Offensive Buffs from all enemies.
Decrease Buster Card Resistance by 20% for all enemies (3 turns).

<Overcharge>

Deal supereffective damage to [Earth] attribute enemies.

Show Info/Video

Tunguska Nine Drive

Thunderous Heavenly Light - The Calamitous Star Crashes Down in Waves of Flame

	Rank	Classification	Hit-Count
	C	Anti-World	5

Effect	Increase own ATK by 20% (1 turn) [Activates first]. Deal damage to all enemies. Remove Offensive Buffs from all enemies. Decrease Buster Card Resistance by 20% for all enemies (3 turns).

Level	1	2	3	4	5
Attack +	20%	20%	20%	20%	20%
Damage +	300%	400%	450%	475%	500%
Buff Removal
Buster Res -	20%	20%	20%	20%	20%

Overcharge Effect	Deal supereffective damage to [Earth] attribute enemies.

Charge	100%	200%	300%	400%	500%
Supereffective ATK +	150%	162.5%	175%	187.5%	200%

Tunguska Nine Drive is, fortunately, a pretty good NP. It gets two separate damage boosts: a one-turn pre-cast attack up, and a three-turn post-damage Buster resistance debuff. What this means in practice is that Koyan gets good NP steroids in any context, but that her damage snowballs only in hard fights, and not while farming. Hard to complain about this, really—it works well for Koyan as a DPS, and the Buster resistance debuff is nice if you’re trying to use her as a support. The NP then deals AoE damage, with a supereffective modifier against Earth enemies. Attribute-based damage buffs are pretty nice in that they’re large niches, which holds true here even though Earth is not the largest attribute group. It’s also worth remembering that Koyanskaya of Light grants power mod versus Man enemies, so between the two effects, Koyanskaya of Darkness will get bonus damage against a substantial portion of the cast. The NP also removes offensive buffs, which can occasionally be helpful for survival in hard fights. If Koyan had a more synergistic DPS kit, this would be a great NP. As it is, though, it’s just alright.

Usage Tips

Koyan can farm in traditional Buster battery looping ways with Koyanskaya of Light/Koyanskaya of Light/Oberon. Koyan needs a 50% charge CE to do this, and she also needs Mana Loading maxed (although she can also use Kaleid if her damage is high enough). She uses her first skill on turn 1, relies on Koyan of Light batteries turn 2, and uses her first skill again in conjunction with Oberon on turn 3. She won’t be farming with other non-Arashlike setups, but this should work well enough for general use, especially for nodes whose enemies fall within Koyan’s various niches. Her damage isn’t spectacular, and there are plenty of better farmers, but she can work at least.

Koyan is a lot more interesting in CQs. She can work as a semi-support for Kemono Servants, and although she’s not great in that role, she’s an option for players without many Buster supports. There isn’t a specific team setup that makes this work well—instead, you can consider Koyan a sort of backup support to fill whatever holes you happen to have. You run her with a Buster DPS with the Kemono trait and whichever Buster support you do have and hope for the best. If you don’t have any Buster supports, I would suggest picking Merlin off your friend list—you’ll probably end up needing some sustain, and Merlin is better at stalling fights out than Koyanskaya of Light and Oberon are.

Koyan’s kit is a lot cleaner when she’s used in a DPS role. Koyanskaya of Light/Koyanskaya of Darkness/Koyanskaya of Light/Oberon is a decent burst team—not as good as… well, most other AoE Buster options, but not a terrible one. You can also run something like Merlin/Koyan/Castoria for a more stall-oriented team that gets better use of Koyan’s AoE battery and NP charge skill. You can also, as always, scale down to lower-rarity supports if you don’t have the meta options. Base Mash is actually a pretty good partner here, as Koyan will end up with substantial defense buffs in play, and Koyan can toss her Overcharge buff to Mash for even more defense.

Koyan’s best team, though, is without a doubt double Van Gogh. Van Gogh/Koyan/Van Gogh has massive crit damage on all three Servants. All three Servants benefit heavily from Koyan’s first skill, and Koyan’s Overcharge buff can strengthen the attack buffs on one of the Van Gogh NPs. Koyan’s curses can fuel extra NP charges for Van Gogh, too, as an added bonus. Van Gogh teams are also missing pierce invuln by default, and while this isn’t a huge deal given Van Gogh teams’ stability, the potential to maintain tempo even in the face of incidental dodges and invulns is a nice plus.

Koyan’s CE choice depends largely on how you plan to use her. In farming contexts, she needs starting NP CEs. Event CEs with 50% charge are ideal of course, but outside of that CEs that provide charge and damage are great. Aerial Drive, Holy Night Summer, Demonic Heavenly Princess, and Golden Sumo are all good choices. As a support, Koyan either wants starting NP (for easy access to the Buster debuff on her NP) or 2030 to help with crit enabling. In Van Gogh teams, Koyan has a lot more flexibility. Since she’s likely going to stick around for a while, CEs that don’t provide starting NP but instead provide other benefits can be good. 2030 still works here, although the stars may be overkill. Prisma Cosmos can help enable more frequent NPs, and CEs that provide non-crit damage buffs (such as Limited Zero Over) can increase the team’s tempo.

Koyan doesn’t have any obvious CC needs. Star gen CCs can be a good choice, as she has decent crit potential but few ways to gain stars. Some extra incidental star gen can let Koyan leverage her third skill more effectively, or help other Servants crit past Koyan’s star weight.

Grail Potential

Conclusion

Koyan has enough about her that’s just sort of intrinsically strong that she avoids being out-and-out bad despite the confused and anti-synergistic nature of her kit. That said, she comes out looking no better than mediocre. She’s highly limited as a supportive unit and not even all that effective in-niche, while as a DPS she has limited Koyanskaya of Light synergy and struggles to keep up with most other AoE Buster options. She’s usable, at least, and her Van Gogh synergy props her up a little bit, but by and large she’s pretty meh. An easy skip for most players, at least gameplay-wise.

Rabbit's Arbitrary Ratings

Overall: 7/10
Single-Target DPS: 4/10
AoE DPS: 7/10
Survivability: 4/10
Offensive Utility: 6/10
Defensive Utility: 3/10
Farming Usefulness: 6/10
Casting Meteor Swarm: 10/10