I, Who Will Die at Thirty, Am a Teacher at Teitan High School

Sakurakoji Yuu has the ability to transmigrate consciously. At eighteen, he was named by Time magazine as "the mathematician most likely to change the world," yet he went off to teach at Teitan High School. The reason was simple: he would die at thirty. He had died once, only to be brought back by people in the future, but his fate remained unchanged. He needed to leave descendants, so that future generations could save him once again. In his class were Shiki Ryougi in a kimono, the twin-tailed Rin, Kagome Higurashi, and the AI girl Atri, whom he had brought back from the future. He had planned to teach quietly and leave behind an heir. That was, until someone went on a killing spree in the rain, wearing Shiki Ryougi's clothes. "...Shiki, go take a look."