Taikutsu-girai no Fuuinjutsushi

"If I put my life in a notebook, it would end in one page."

Seal, a young man in prison, had so much spare time. Closed space, unchanging scenery. Every day he read books inside the prison cell. A boring life that made him feel like he was going insane. Then, a newcomer came to his prison cell. His name was Barha Zetta. 79 years old, male. Occupation―sealer. Seal was interested in the job of Barha-Zetta and became his disciple to kill time...without knowing that it would bear the fate of the world.

(Source: Shousetsuka ni Narou, translated)