Eirin is a lunarian pharmacist, and Kaguya Houraisan’s bodyguard. She’s a skilled pharmacist who can make any medicine, and owns a pharmacy called Eientei. She has a bad habit of spoiling Kaguya with attention and praise. Eirin is prim and proper with a strict exterior, but a very sweet inside. She loves her partner dearly, and also loves giving lap pillows. Her “pet” bunnygirl pharmacist assistant is Reisen Inaba. She loves calling people petnames. She knows Sagume Kishin as well.