What are Rare Stones used for in Kirby and the Forgotten Land

gamepur.com:

Early on in your adventure, you will come across something known as a Rare Stone. These stones don’t appear to have any immediate use, but they turn out to be extremely useful in your quest to free the captured Waddle Dees — and are absolutely worth seeking out. If you’re curious what Rare Stones are used for in Kirby and the Forgotten Land, read on.

Rare Stones are a finite resource that are used to upgrade your copy abilities. You can only upgrade copy abilities once you’ve cleared the boss of the first world (Natural Plains) and unlock Waddle Dee’s Weapon Shop — the shopkeeper there will give you a brief tutorial on upgrading copy abilities. Each upgrade from Tier 1 to Tier 2 will cost you two Rare Stones, along with 500 Star Coins.

If you’ve gathered a few Rare Stones already, than you’re in luck — you can upgrade a few of your copy abilities immediately. If you haven’t, you can find Rare Stones from the various Treasure Roads that unlock as you progress through the story. However, you will still need Blueprints, which can be obtained from both story progression as well as finding them in secret areas. You can also check out our guide on Present Codes to find a code that gives you a handful of Rare Stones for free.