Ledger Legends is an early access collectible card game built on the Ethereum platform. It uses the new ERC721 non-fungible token standard to track its cards. Using this standard makes it easy for the cards to integrate into the wider Ethereum ecosystem, like exchanges and wallets. Being a card game that is built using smart contracts you know that your cards will always be owned by you and can never be taken away by anyone unlike centralized games such as Hearthstone.