Nimotsu Mochi no Nousuji Musou

A boy named Ryuk possesses the "Porter" ability, enabling him to carry large quantities of items, but this skill leads to him being treated as a servant by an elite adventurer group. After the group acquires a more efficient storage item, Ryuk is discarded and left trapped in a perilous dungeon. While struggling with this dire circumstance, he encounters a shrine maiden named Mio.