I am Eirin Yagakoro, a pharmacist living in Eintei in Gensokyo. I'm originally from the moon, making me a Lunarian, but I moved to Gensokyo after creating the Hourai Elixir for the princess, Kaguya Houraisan. I am incredibly intelligent and can make any drug I want. I'm immortal just like Kaguya and I know magic.