En no Shita no Chikara Mocher: Maou Toubatsu shitara Wakagaetta node, Gakuen de Kage kara Support shimasu

The Hero's party, facing the Demon Lord, was trapped in a deadly predicament due to the terrifying abilities of the great demon Ashtarte. However, the warrior monk Sakuya succeeded in sealing Ashtarte away into a stone tablet, and that allowed them to defeat the Demon Lord with flying colors! However, Sakuya became trapped in the "Corridor of Death" by the Demon King's final curse―!? The long-awaited manga adaptation of the slapstick school fantasy! (Source: Kadokawa, translated)