High school biology teacher Tetsuo Takahashi may look like your average everyday instructor, but beneath his gentle appearance lies something less ordinary: his fascination for the "Ajin," more commonly known as "Demi." Although these half-human, half-monster beings have integrated into human society, Takahashi believes that much about them will remain unknown unless he interacts with them firsthand. Demi-chan wa Kataritai follows Takahashi's daily life in Shibasaki High School together with his three Demi students—Hikari Takanashi, an energetic vampire; Kyouko Machi, a gentle dullahan; and Yuki Kusakabe, the shy snow woman. Along the way, Takahashi also meets fellow teacher Sakie Satou, a succubus with an aversion towards men. To fulfill his goal of learning more about the Demi, Takahashi decides to conduct casual interviews with the girls to learn more about their abilities, psyche, and interaction with human society. As Takahashi strengthens his bond with his students, he soon discovers that the Demi are not as unusual as he initially believed. [Written by MAL Rewrite]

Hikaru Kusakabe is a normal, carefree boy in a rock band who is always focused on the present. During the summer, his entire class is forced to participate in an upcoming chorus festival. By coincidence, he discovers his classmate Rihito Sajou—known for being an honor student with excellent grades—practicing his singing alone. Sajou just cannot seem to get their class' song right, and Kusakabe, delighted at seeing a new side of his straight-laced classmate, offers to help him prepare for the event. Although their lives and personalities are total opposites, they begin to grow closer as time progresses. But with the pressure of an unknown future, what will become of them and their growing relationship? [Written by MAL Rewrite]

The atmosphere in True Cross Academy is lively and boisterous in the days leading up to the grand festival held once every 11 years. During this time, Okumura Rin is entrusted with the responsibility of suppressing the berserk Phantom Train. In the midst of his mission, he meets a devil whose appearance is that of a young boy.

(Source: Official Site)

Feeling slighted by Rin, Kuro goes on the hunt for a new master, but can he find anyone who can truly replace Rin?