Eirin Yagokoro (Eternal)

A8 Eirin Yagokoro was released on July 1st, 2022 in Festival: Imperishable Sage & Night Sparrow.

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, making her an S-Tier threat.

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!