Yagokoro Eirin Rule 34

Yagokoro Eirin is a major character in the Touhou Project series, known as the Brain of the Moon. She is a Lunarian pharmaceutical genius who created the Hourai Elixir, granting immortality to her friend Houraisan Kaguya and later to Fujiwara no Mokou. Since then, she has served as Kaguya's bodyguard and caretaker at their mansion, Eientei, and is also the mentor of the lunar rabbit Reisen Udongein Inaba. In Gensokyo, she acts as the chief pharmacist. Eirin has a mature demeanor and is often grouped with other long-lived characters. Her appearance includes a hat with a red cross symbol, a dress adorned with trigrams forming the bagua, and constellations sewn into the fabric. Fans frequently depict her with medical or lunar motifs, and she is associated with the rallying cry 'Eirin! Eirin! Tasukete Eirin!' that originated from Kaguya. Her surname references the Shinto god of intellect and wisdom, leading to speculation that she may be Omoikane herself.