Morio Tanaka is a teacher and the P.E. coach at Jinbou Elementary. He is in a relationship with Mitsuya, who is Sana, Hayama, and the rest's teacher. Hayama, early in the series, gets a picture of them kissing and threatens to reveal it, which could cause both teachers to be brought to shame. He uses this as blackmail to allow him and his friends to torture Mitsuya, while Tanaka can do nothing to prevent it.
Eventually, Sana uses a plan to get the picture destroyed. It is revealed, however, that he still keeps a copy, and uses this against him when another teacher, Sumirei Ando, intends to give out a test which Hayama knows Sana will not pass. His plan works, though it is later discovered that the image he had was a fake.
- His first name is learned in Love Tastes Like Curry.