Mystical Taurus Shard

The materials needed for this recipe are dropped by Trash and Bosses in .
We are told that this item can be "used" to add a special enchantment to any of the , , or dropped by Bosses in . Other than that we have no specific information.
When using to upgrade the rarity of a , , or , their durability, enhancement level, or Stats will not be modified. Players won’t need to worry that they will lose the enhancements and upgrades that are already on the Accessories. --from 5/7/2024 patch notes
According to Ainz on RoM Discord, Rare can become Epic, Epic can become Legendary. He also said that "50% chance that is went up, 50% chance that you'll get a blue item after that".
So, can become , which can become . The Stats and Durability remains the same. What changes is, you need 2 or 3 of the same Color and Naming to get the Set Bonuses.