Upgrade and Evolve Tier Items
By using Crystal Upgrade on an item, we can increase its level. A higher level increases the stats of Item Level, Attack, Armor and Defense.
Upgrading to level 8 only requires gold. Over level 8 requires items that can be found on individual monsters. More here: Armor and Weapons or here Accessories
When an item reaches level +15 an additional item is required that can be obtained from dungeons. We have a chance to turn the item into a higher tier that increases all the stats of the item.