If you apply the ascension stone to an item it will grant it the ability to level up by using it. The levels don't impact the game a lot so it's fully vanilla friendly.
By using the De-Ascension stone on an item that can be leveled you will remove the ability to level from it.
Shields, Weapons, Armors and ranged weapons such as bows and crossbows have all unique traits to upgrade, for example: you can level the bow ranged damage for the bow, you can level a sword or an item attack speed or reach, you can level the protection of an armor and much more! (These are just examples you can usually level up to 3 traits per category of weapons)
Leveling Weapon/Item GUI (v2.0):
Leveling Armor GUI (v2.0):
