Marina Koizumi (小泉（こいずみ）まりな) is a teacher of Sakura-en Public Elementary School. She debuts in Episode 7 of Miyakawa-ke no Kufuku and is voiced by Natsumi Yamada.
Appearence and Personality
She is a colleague of Mr. Osawa. She has long, orange hair and has a elusive personality. Her catchphrase is "Aaah~" (あぁ〜〜〜〜).