Spirit stones or Spirit cores, were a type of green coloured course that is dropped by a monster in a dungeon once they are killed.
Compared to the red coloured cores of the monsters outside, the spirit cores are green in colour and their quality depends upon their size.
The most important difference between the normal cores and the spirit cores is that while mana cores help in gaining more mana and increase the maximum power temporarily when consumed in high amount,
The spirit cores increase the potential of the System itself. It was a well known fact among the people during the later stages of the second Cataclysm and it was one of the reasons the dungeons were so popular.
You can upgrade your system from A-Rank to S-Rank and beyond, and the very thought of becoming a better rank was enough for the masses to give at least one try in these dungeons.
