Hoshikui Killer Egnaro

Set in a world riven by a strange rift that extends deep into the ground, the people dig into it to search for the resources known as "inheritance." The story begins when a traveler visits a village in poverty because no matter how much they dig, they cannot find any inheritance. The traveler locates a potential vein in the mine, and goes with the villagers to dig into it.

(Source: Natalie, translated)