Dungeon ni Tojikomerarete 25-nen. Kyuushutsu sareta Toki ni wa Rippa na Fushinsha ni Natteita

The year is 2025—dungeons suddenly started popping up all over the world. A young man, Hiroshi Nagano, ventures into one of them, but ends up trapped in the dungeon’s uncharted depths…for 25 years! By devouring ferocious monsters, he not only survives, but builds a legendary physique. When he finally makes it back to the surface, he’s greeted to a Japan of the future, where streaming your dungeon exploration is mandatory. His overwhelming power is broadcast to the nation, propelling him straight into the ranks of top dungeon explorers! Using a quarter-century of brutal survival instincts, a shady-looking veteran is about to dominate the algorithm in this thrilling, over-the-top heroic dungeon tale!

(Source: Square Enix)