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Eirin Yagokoro (Eternal)

3018
Fes
Brain of the Moon (Eternal)

Stats

Element Type Chart

Tsukigasa
Expand
Tsukigasa (a Touhou LW original) refers to an atmospheric optical phenomenon in which a halo appears around the moon. This is an apt temperament for Eirin, who created a fake full moon and sealed the surface. Eirin is endowed with Fire Phase, as she sought change and not constancy, and Moon Essence, as a sage of the moon.

The formless and passionate Fire Phase resists Wood Phase, because wood feeds fire, but it is weak to Water Phase, because water dampens fire.

The cooperative and indecisive Moon Essence resists the alluring and arrogant Sun Essence, but it is weak to the diverse and uncooperative Star Essence.
sun_weak
Sun
moon_neutral
Moon
fire_neutral
Fire
water_strong
Water
wood_weak
Wood
metal_neutral
Metal
earth_neutral
Earth
star_strong
Star

Character Shots

The Spread Shot of Eirin Yagokoro from the world of eternal night (a Touhou LW original). She summons destructive innovations in this attack. Although Eirin is a genius, she is not the kind of sage that just sits at home and doesn't act. This attack is the ultimate battle of wits that challenges the opponent to think empirically and logically. This challenge by a true sage also tests whether the opponent has the courage to take decisive action, like how Eirin fearlessly saved Kaguya. Shooting at the moon is a fool's act, but a sage can actually hit the moon. She may be an example of someone who has completely mastered the art of battles of bullets.
All
Waxing Gibbous Shot
x10 Yin
All
Eve of the Full Moon Shot
x2 Yang 1
All
Full Moon Shot
x2 Yin 2
All
Night After the Full Moon Shot
x2 Yang 2
All
Waning Gibbous Shot
x2 Yin 3
All
Last Quarter Shot
x2 Yin 3
The Focus Shot of Eirin Yagokoro from the world of eternal night (a Touhou LW original). She manifests educational guidance in bullet form. This attack is essentially Eirin's instructional whip as a teacher of the moon. It is not exactly known what kind of mental process lunar thinking is, but Reisen Undongein Inaba seems to have mastered it. Although youkai are very different from humans, Lunarians are actually considered to be the most alien beings from humans. The more distant a lifeform is from humans, the more difficult it is for humans to guess their ecology and thoughts. This is because humans can only come up with ideas based on what they themselves have experienced.
All
Lunar Thinking: Introduction
x6 Yin
All
Lunar Thinking: Basics
x2 Yin 1
All
Lunar Thinking: Application
x2 Yin 2
All
Lunar Thinking: Practice
x2 Yang 3
All
Lunar Thinking: Advanced
x2 Yang 3
All
Lunar Thinking: Secret Technique
x2 Yang 3

Character Spell Cards

Available
Available
Limit Break 1
Limit Break 2
Limit Break 3
A Spell Card of Eirin Yagokoro from the world of eternal night. This attack imitates the forbidden elixir. The fates of Eirin and Kaguya were drastically changed when Eirin created the Hourai Elixir with Kaguya's ability. Whoever consumes the elixir will become a person of Hourai, a being with true immortality that can never perish. In return, they will become impure and can no longer live on the moon. The name ''Hourai Elixir'' could mean a ''medicine from Hourai,'' but it is also possible that Eirin just named it after Kaguya. If Kaguya could make a medicine of immortality, all the authorities on Earth would surely fight over her. Still, Kaguya would probably reject everyone and continue to be an anti-Cinderella... But the real question is, how does this medicine taste? Is it bitter?
*Pre- and Post- effects assume max level. Effects per level can be viewed here.
Pre-Attack Spell Card Effects
Inflicts 2 layer(s) of Barrier Status: Poison to self (3 turns).
Post-Attack Spell Card Effects
Adds 2 layer(s) to own Barrier.
Solo
Hourai's Light
x16 Yin
Solo
Hourai's Elixir
x4 Yin 1
Solo
Hourai's Illumination
x4 Yin 2
Solo
Hourai's Mysterious Medicine
x4 Yin 2
Solo
Hourai's Vivid Light
x4 Yin 3
Solo
Hourai's New Medicine
x4 Yin 3
A Spell Card of Eirin Yagokoro from the world of eternal night. She creates a starry sky within a jar that has no inside or outside. This sealed area without boundaries is Eirin's secret technique that completely separates the moon and the Earth forever. Her pupil and the greater youkai, who rely on boundaries to travel between the moon and the Earth, will probably struggle to use their abilities if Eirin uses this attack. It is similar to a black hole, without a doubt.
*Pre- and Post- effects assume max level. Effects per level can be viewed here.
Pre-Attack Spell Card Effects
All targets' CRIT DEF 2 level(s) DOWN (3 turns).
Post-Attack Spell Card Effects
None
All
Jar's Star
x15 Yin
All
Jar's Sun
x4 Yang 1
All
Jar's Moon
x4 Yin 2
All
Jar's Constellation
x4 Yang 2
All
Jar's Fixed Star
x4 Yin 2
All
Jar's Satellite
x4 Yang 3
The Last Word of Eirin Yagokoro from the world of eternal night (a Touhou LW original). This attack differs from the original because it was merged with her spell, which creates a sealed room. She uses multiple surveillance networks to observe the moon and the Earth. They are said to be set up somewhere between the moon and the Earth, somewhere that can never be identified since the boundary between them has been erased. This place could be in the Dream World or another dimension. The only thing that is certain is that this is the Net of Eternal Wisdom that Eirin created to protect the princess and Eientei for eternity.
*Pre- and Post- effects assume max level. Effects per level can be viewed here.
Pre-Attack Spell Card Effects
Own CRIT ATK 3 level(s) UP (2 turns).
Own Yin DEF 2 level(s) UP (2 turns).
Inflicts 2 layer(s) of Barrier Status: Blind to all targets (2 turns).
Post-Attack Spell Card Effects
None
All
Fake Moon's Light
x20 Yin
All
Ground Monitoring Bit
x4 Yin 1
All
Heaven Net
x4 Yin 2
All
Spider Net
x4 Yin 3
All
Moon Monitoring Bit
x4 Yin 3
All
Butterfly Net
x4 Yin 3

Character Ability

Capable of making any drug. Natural genius.
Expand
The ability of Eirin Yagokoro from the world of eternal night (a Touhou LW original). It is essentially the same as our version of Eirin's ability. She can create any medicine with her amazing skill if she has the right ingredients. She also has an outstanding mind that is not limited to just the field of pharmacy. She is one of the Sages of the Moon, and her intelligence is so great that she was even consulted for advice by Tsukuyomi, who is said to be the founder of the Lunar Capital. It seems that the Eirin of this world is more than capable of prolonging the Eternal Night Incident...

While Eirin serves Kaguya, she is also Kaguya's teacher and kind of like her mother or guardian as well. Their relationship is more complicated than a simple partnership. Although Kaguya's abilities are complex, unknown, and expected to be very powerful, it is thought that Eirin has utilized her abilities to create the Hourai Elixir, an immortality medicine. This means that Eirin is at least familiar with Kaguya's abilities and may even completely understand them. It is theorized that Eirin did not just receive Kaguya's help by giving her specific instructions but also performed the extraordinary feat of turning the concept of Kaguya's abilities into an ingredient for medicine. This hypothesis is possible only because Eirin possesses a genius brain and ultimate pharmaceutical skills. And if this hypothesis holds, Eirin should also be able to fully comprehend the abilities of her other students, the Watatsuki sisters, and maybe even materialize their abilities into ingredients for medicine.

Unlike our world's Eirin, the Eirin of this world has not managed to come to the conclusion that Gensokyo's barrier alone can sufficiently shut out the moon emissaries. This has directly led to the incident being prolonged, meaning that Eirin's secret technique, which created a sealed chamber by swapping the full moon with a fake moon, was never broken. The eternal night that was created to combat this spell must have also been extended somehow.

Perhaps this Eirin's method of creating a sealed chamber was different from what happened in our world. It is unclear how the Eirin of our world performed her spell, but it is possible that this Eirin performed it by manifesting someone else's ability. Thus, it can be assumed that the Eirin of this world also caused the incident to test her spell. The test must have been successful, meaning there was no need to worry about an invasion from the moon emissaries. And even if something unexpected occurred, Eirin could prevent any attack by copying the enemies' abilities as ingredients for medicine, which she could then apply to her spell. Since this would block intrusion more reliably than Gensokyo's barrier, Eirin no longer had any reason to undo her seal on the surface...
For every layer of Barrier Status: Poison or Blind, Yang DEF Yin DEF, CRIT DEF, and CRIT Evasion 1 level UP.
DMG to effective elements 20% UP.

Character Skills

CD 4
Inflicts 2 layer(s) of Barrier Status: Poison to self (3 turns).
Inflicts 2 layer(s) of Barrier Status: Blind to self (3 turns).
Info
A compound medicine that can be used as both poison and medicine. The ingredients are dragon's blood, tree resin, cinnabar, and Calamus Draco.
Skill Level 1 2 3 4 5 6 7 8 9 10
Barrier Poison
Value 1 1 1 1 1 1 1 1 1 2
Rate 0 10 20 30 50 50 60 80 80 0
Add 0 1 1 1 1 1 1 1 1 0
Barrier Blind
Value 1 1 1 1 1 1 1 1 1 2
Rate 0 10 20 30 50 50 60 80 80 0
Add 0 1 1 1 1 1 1 1 1 0
CD 6 6 6 6 6 5 5 5 4 4
CD 6
Inflicts 2 layer(s) of Barrier Status: Poison to target (3 turns).
Inflicts 2 layer(s) of Barrier Status: Blind to target (3 turns).
Target's Yin DEF 2 level(s) DOWN (2 turns).
Info
A poisonous drink that induces a state of severe intoxication. Ingredients are rice flour, syrup, and madhuca flowers.
Skill Level 1 2 3 4 5 6 7 8 9 10
Barrier Poison
Value 1 1 1 1 1 1 1 1 1 2
Rate 0 10 20 30 40 50 60 70 80 0
Add 0 1 1 1 1 1 1 1 1 0
Barrier Blind
Value 1 1 1 1 1 1 1 1 1 2
Rate 0 10 20 30 40 50 60 70 80 0
Add 0 1 1 1 1 1 1 1 1 0
Yin Defense Level Down
Value 1 1 1 1 1 1 1 1 1 2
Rate 0 10 20 30 40 50 60 70 80 0
Add 0 1 1 1 1 1 1 1 1 0
CD 6 6 6 6 6 6 6 6 6 6
CD 4
Own Spirit Power 1.00 UP.
Party's Yin ATK 2 level(s) UP (2 turns).
Party's Accuracy 2 level(s) UP (1 turn).
Info
This is the generic form of an elixir from China that is said to sharpen the senses. Ingredients are stalactite, red halloysite, sulfur, white quartz, and purple quartz.
Skill Level 1 2 3 4 5 6 7 8 9 10
Spirit Power Up
Value 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.9 0.9 1
Rate 0 0 0 0 0 0 0 0 0 0
Add 1 1 1 1 1 1 1 1 1 0
Yin Attack Level Up
Value 1 1 1 1 1 1 1 1 1 2
Rate 0 10 20 30 40 50 60 80 80 0
Add 0 1 1 1 1 1 1 1 1 0
Accuracy Level Up
Value 1 1 1 1 1 1 1 1 1 2
Rate 0 10 20 30 40 50 60 80 80 0
Add 0 1 1 1 1 1 1 1 1 0
CD 5 5 5 5 5 5 5 5 4 4

Character Characteristics

Hourai Body
When attacked, DMG from Sharp Bullet 30% DOWN. [Success rate 100%.]
Too Much Fun Is Poison
When wave starts, inflicts 1 layer of Barrier Status: Poison to target (3 turns). [Success rate 30%.]
Royal Guard
After being attacked, own Yin ATK 1 level UP (3 turns). [Success rate 75%.]

Character Change Effect

Guard Link
When switching places with a rear-guard unit, other unit's Yang DEF, Yin DEF, CRIT DEF, & CRIT Evasion UP (3 turns).
When switching places with a front-guard unit, inherits part of other unit's Yang DEF, Yin DEF, CRIT DEF, & CRIT Evasion buffs (3 turns).

Upgrade Costs

Rank Coins Materials
0 -> 1 1000
1 -> 2 2,000
2 -> 3 5,000
3 -> 4 10,000
4 -> 5 15,000

Character Analysis

A8 Eirin Yagokoro was released on July 1st, 2022 in "Festival Prayer: Imperishable Sage & Night Sparrow." For more up-to-date analysis, be sure to visit the Discord Official Discord Server.

Eirin Yagokoro is known as the Brain of the Moon due to her immense wisdom regarding Lunarian technology, thanks to her being one of the founders of Lunarian society. The history of her life is immensely long, but the main inciting incident was when she told Kaguya to create and drink the Hourai Elixir, a crime fit for exile to the Lunarians. The princess’ exile on Earth eventually ended, but when Eirin was assigned with other rabbit emissaries to bring Kaguya back to the Moon, she killed the rabbits and escaped back to Earth with Kaguya. Even in the timeless mansion of Eientei, having the runaway moon rabbit, Reisen Udongein Inaba, be able to find the place made Eirin paranoid of being discovered. To ensure no Lunarians found the exiles, Eirin cast a spell to replace the real Moon with a fake one to prevent Lunarains from entering Gensokyo. The incident resolvers and youkai of Gensokyo quickly took notice of the fake Moon and began to attempt to take down the lunar sage. Eirin tried her hardest to protect the eternal resting place of her princess, Kaguya, a determination she carries in this alternative form in LostWord.

Focusing more on offense rather than her medical background, Eirin can actually do some decent immediate damage and farm a few story card stages. Her Last Word, Heaven Spider’s Butterfly - Capturing Web - False Moon, is able to land critical hits on a good amount of opponents thanks to Human-Killer and Youkai-Killer tags, which is supported by the pre-ATK effect of the attack buffing her CRIT ATK by 3 levels (2T). Some setup can be done with her second spell, Medicine Sign: Great Galaxy in a Jar, to decrease all foes’ CRIT DEF by 2 levels (3T) for even more critical damage. The Last Word itself is overall strong as well, even if her Hard scaling is rather minimal in relevance. The various buffs on her kit, somewhat including the defensive buffs she gets from being inflicted with Poison or Blind anomalies, makes Eirin a good pick for quick damage.

When it comes to challenging content, Eirin is usually either setting up her damage even more or providing slight buffs and assistance to the rest of the team. Her second skill, Sura With Soda, inflicts 2 layers of Poison and 2 layers of Blind on a singular enemy, with the Poison being able to serve as a Yang DEF debuff if the barriers aren’t broken. Eirin herself can also break Poison at 1P of her Last Word and Blind at 3P of her Last Word, giving her some utility in terms of anomaly breaking. The skill also debuffs a target’s Yin DEF by 2 levels (2T) to provide indirect buffs to the rest of the team. Skill 3, Five Minerals Powder, contains some more direct buffs, specifically providing 2 levels of Yin ATK UP (2T) and Accuracy UP (1T) to all allies. It also gives Eirin 1.00 Spirit Power, which can be helpful for accessing more elemental breaks and somewhat makes the backloaded nature of her Last Word easier to deal with.

Speaking of elemental breaks, Eirin’s kit is both good and bad in this aspect, in a sense. First off, her Focus shot, Lunar Thinking, is an easy 0P Moon break on all targets, already giving her a great spam option for stages where Moon is advantageous. Otherwise, however, Eirin’s spells are filled with an interesting mix of elements. Specifically, both of Eirin’s normal spells, Forbidden Medicine: Hourai Elixir and Medicine Sign: Great Galaxy in a Jar, have 2 Moon, 2 Sun, and 2 Star attached to them, which actually makes Eirin a rather below-average breaker in all 3 elements when only considering these spells. Heaven Spider’s Butterfly - Capturing Web - False Moon fares slightly better, being more focused with 4 Moon but still has 1 Sun and 1 Star on it, making it a little uncomfortable when going only for Moon breaking. The attack itself isn’t even singular in terms of bullet types, being 2/3 Laser and 1/3 Light, making optimizing its damage also somewhat challenging. At the very least, Eirin’s access to Poison and Blind breaks makes up for Eirin’s elemental performance to make her a decent breaker still.

Overall, Eirin is really only around to strike opponents hard while using her medicine on the offensive, either to inflict herself with even more defensive buffs or apply anomalies on foes. She sadly cannot provide much else outside of this, which really shows when it comes to team utility or even specific elemental breaks. At the end of the day, though, Eirin does a very good job at nuking the enemy with Yin damage and still has utility via anomaly breaks and even some buffs and debuffs. She may still not be trusting of other humans, youkai, or…anyone else, honestly. But while she’s on your team, using her to her maximum potential will definitely be rewarding!

Story Card Recommendations

Spell Card

Eirin, just like any other Friend, will never say no to the great Spirit Power increase that comes from equipping The Witch of Scarlet Dreams onto a spell card. The rest of her spell card slots can be contributed toward making her damage even better. This can come from Yin ATK buffs, with a special mention to Mansion of Memories for granting the whole party the buff and having a great Yin ATK stat stick. If you’re aiming for the enemy’s vitals and going for CRIT ATK UP, try Miracle Mallet’s great 3 extra levels of CRIT ATK UP.

Last Word

While Eirin’s mix of elements and bullet types makes her Last Word more of a puzzle to support, Unmoving Great Library can save the day due to buffing both Moon attacks and Laser Bullets, which make up most of her Last Word. Otherwise, there are times where you can be sneaky and try out Anniversary at the SDM, which has a good Yin ATK stat stick, a great Yin DEF debuff, and even Laser Bullet buffs! For something even more specific, you can go for more CRIT ATK buffs, such as the ones in Standing Behind You, which buffs Moon damage as well!

Character Skill Level Up Recommendations

The first skill that should be immediately prioritized in leveling is definitely Eirin’s third skill, Five Minerals Powder. Not only does it allow her to reach 2P on turn 1, but it will increase the amount of Yin ATK and Accuracy she provides her allies and even decrease the skill’s cooldown to 4 turns. Afterwards, her second skill, Sura With Soda, is a good candidate due to increasing the amount of anomalies Eirin inflicts, which likewise can end up making her deal more anomaly breaks later. The Yin DEF debuff changing from 1 to 2 levels is also good for team support. Eirin’s first skill, Drachenblut, may be last in priority, but it still provides great defensive buffs thanks to Eirin benefitting from self-inflicted anomalies, and the decreased cooldown can come in handy for longer fights.

Character Strengths

+ 0P All-target Moon on Focus shot
+ Good Yin nuking potential on Last Word thanks to Killers
+ Niche in Poison and Blind anomaly breaks
+ Slight CRIT and Yin support

Character Weaknesses

- Limited Hard scaling and mixed bullets makes her difficult to optimize
- Elemental breaking on spells is a mixed bag
- Team utility she provides is still on the lower end