Solo Leveling Wiki

Essence Stones are small glowing stones that are found inside the corpses of Magic Beasts. They are generally very valuable and serve as the primary source of income for most hunters around the world.

Naturally, an essence stone's worth is determined by its rank and quality. As a result, E-Rank essence stones sell for very little cash since they are so common and low-quality, while S-Rank essence stones sell for millions due to how rare and top-quality they are.

Although the reason why essence stones are so valuable is never actually explained, it is implied that they are a long-lasting and highly efficient energy source, given that Kamish's essence stone was used to power the FBH's HQ for nearly a decade. It is also later revealed that the Rulers created essence stones and implanted them inside the magic beasts that they captured during their first war with the Monarchs to have them kill humans and in turn, saturate the human world with large amounts of mana so that mankind wouldn't be wiped out during their eventual rematch with the Monarchs.

Colors Magic Beast Ranks
Grey Essence Stone (??) Rank E
White Essense Stone Rank D
Yellow Essense Stone Rank C
Blue Essense Stone Rank B
Red Essence Stone Rank A
Purple Essence Stone Rank S