Tarisa Warinai 
DUNGEON DIVE: Aim for the Deepest Level Volume 10 (Light Novel) [EPUB ebook] 

Titee, the Thief of Wind’s Essence, stands in the way of Kanami’s return to the surface! At the same time, the town of Viaysia is rolled back to its devastated state of a thousand years ago. Nosfy, full of both love and hate, won’t allow Kanami to escape to his future aboveground. But Kanami, who has vowed to atone for all his sins, uses the price of incantations as a way to get a glimpse of a possible future. It is a story that spans 1, 111 years—a childish game of make-believe started by a vain sorcerer.
“Why?”
“Why did you go that far?”
At the end of a trial of the fiftieth floor awaits myriad scenes from someone’s childhood…