Luna Koizumi (Koizumi Runa 小泉 月?) is only shown in the manga not in the anime. She is the former friend of Yuka Azumi and now holds complete hatred towards her and her daughter, Mikan. Luna causes problems between Mikan Sakura and Natsume Hyūga by taking on a twelve year-old form. She is in love with the Elementary School Principal and acts as his spy on Mikan and Yuka.