[Spoiler] Things you don’t want to forget

Mana Core Stages:

White Stage - the stage everyone started at. Any basic spells of all categories could be used in this stage, these are Life, Combat, and Enchantment.

Blue Stage - also known as Advance Stage. Any advanced spells of all categories could be used in this stage, these are Life and Death, Nature, Elemental, Elemental Enchantment, and Curses.

Green Stage - the Expert Stage. Any Expert Spells of all categories could be used in this stage.

Yellow Stage

Core Stones:

Low-quality, Medium-quality, and High-Quality. There are cores found from artifacts and monsters.

Artifacts:

Common - any kind of artifact that could be easily found in places held no threats at all.

Unique - any kind of artifact that couldn't be easily found, most of them hold powerful abilities. 

Cultivation: gathering mana from outside sources to the mana core for nourishment and growth.