Tank Chair manga volume 4 features story and art by Manabu Yashiro.

The parapsychic duel between Nagi and Sensei on Guicheng Island is over, leaving the physical and mental landscape an utter ruin. Now our attention turns suddenly to three years in the past… Here, Nagi is Sensei's prize student, a prodigy whom no classmate can match. What events led to Nagi and his sister fleeing the academy and incurring the wrath of the world's deadliest being?