Dungeon Elf: Dungeon ni Takarabako ga Aru no wa Atarimae desu ka

A question that even the most ardent of RPG lovers struggle to answer: Why are there treasure chests placed so conveniently throughout the dungeons? In the grass fields of the Forest of Beginnings, in deadly realms where even the greatest heroes must be prepared to face total annihilation, and even in people’s homes―there, treasure chests sit, aiding unwitting adventurers and maintaining the world’s balance. This is the story of someone, unbeknownst and unnoticed by anyone, who carries those chests.
(Source: K Manga)