NFT items have 5 types of rarity (unique, common, rare, epic, legendary)
NFT items have a slot value: head, body, left hand, right hand, rings.
NFT things can be merged to create a new one. 3 items can merge to create a rare one. 3 are Burn 3 items to create a new one. For rarity types: common, rare, epic, legendary
NFT can change the visual appearance of the hero + add additional characteristics to the strength of the character.