Collector Items are Hats or Body Attachments that are created when a regular item is crafted with a Collectors Stone. These items can be leveled up to unlock new and exclusive Rare Effects. To level up an item, you can craft 5 normal items together with the Collectors version for 1 level up until level 12, or you can craft it with Rare Items of the same type. When adding Rare Items, each tier will give a different number of levels: Tier 3 will give 1 level, Tier 2 will give 2 levels, Tier 1 will give 3 levels, and Golden Cask Effects or Exclusive Effects will give 5 levels. As you level up the item, you can change the effect by using Charges that are gained by leveling up an item. You can give an item unlimited charges by crafting it with a Sigil of Immortality. You can level up an item infinitely with no level cap, however you get the final available effect at level 120.
Available Rare Effects