League of Kingdoms

Discover how ERC-6551 can deliver the promise of interoperable NFT and cross-game gameplay.

What is the ERC-6551 Standard About?

ERC-721 has given rise to various non-fungible token (NFT) applications. However, ERC-721 has two main limitations. One of ERC-721's limitations is that it is unable to own assets. Another of ERC-721's limitations is that it is incompatible with other on-chain assets on the Ethereum network, primarily ERC-20 tokens. The solution is ERC-6551’s token bound accounts (TBAs).

The assets ownership feature of ERC-6551's TBAs enables ERC-721 tokens to be customized by holding NFTs. The compatibility of ERC-6551's TBAs with other on-chain assets enables ERC-721 utility NFTs to have cross-platform functions and gaming NFTs to have cross-gameplay interoperability.

How is ERC-6551 Transforming Web3 Gaming?

Using TBAs, ERC-6551 is transforming Web3 gaming with customizable NFTs. The interoperability of these NFTs allows for cross-game gameplay. In addition, ERC-6551's TBAs also function as smart contract accounts. These accounts can own Web3 gaming assets and verify the transaction history of these assets.

  • Interoperable NFTs

ERC-6551's TBAs are compatible with almost all existing on-chain infrastructures, such as centralized data servers, and off-chain infrastructures, such as decentralized blockchain protocols. This compatibility element allows for Web2 games to be developed into Web3 games. For example, suppose the developer of Pokemon Go, Niantic, wants to tokenize the game's Pokemons into NFTs. Using ERC-6551's TBAs, Niantic can integrate players' Pokemons ownership information on its centralized data servers with decentralized blockchain protocols to tokenize the game's Pokemons into NFTs.

Suppose further that the developer of Digimon World, Bandai, also wants to tokenize the game's Digimon into NFTs. ERC-6551's TBAs enable interoperable NFTs for cross-game gameplay between the Pokemon Go and Digimon World Web3 games. An interesting illustration of the cross-game gameplay possibilities of interoperable NFTs is a Pokemon Go player using a Pikachu NFT to battle an Agumon NFT of a Digimon World player.

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Pokemon vs. Digimon (Source: NerdNightNews.com)

  • Assets Ownership

ERC-6551's TBAs can own any type of on-chain assets. This asset ownership feature enables ERC-6551's TBAs to be used as customizable inventories for gaming NFTs. For example, suppose there is a Pokemon Web3 game that has various NFT assets such as PokeBall, PokeDex, and PokeRadar. ERC-6551's TBAs would function as a Trainer's Bag to store these NFTs as contents in the Bag. The ownership of the NFT assets in the Trainer's Bag customizable inventory will be transferred when the Bag, itself an NFT, is sold.

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Contents of Trainer’s Bag (Source: PocketMonsters.net)

The multi-layer NFT ownership structure of ERC-6551 TBAs allows for a more rewarding gaming experience. This reward element is particularly relevant for NFT assets that form part of a collection or have interdependent functions. Collectible and interdependent NFTs generally have higher market value when sold together as a package than separately. For example, in the epic RPG Diablo IV, a complete set of items can be traded for more Gold as they come with set bonuses. These bonuses provide gameplay advantages by boosting attacking and defensive abilities.

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Diablo IV Set Items (Source: News.Blizzard.com)

  • Credentials Verification

ERC-6551's TBAs can track and store transactions of on-chain assets. This transaction history recording function enables ERC-6551's TBAs to verify the past activities and unlocked achievements of gaming NFTs. For example, suppose there is a Pokemon Web3 game with League achievements in the form of Gym Badges NFTs. ERC-6551's TBAs could track battle record information in the Gym Badge NFTs. This function allows for on-chain verification of the credentials of Web3 gamers to improve user motivation.

Players can tokenize their in-game accomplishments, which opens up endless opportunities for developers and ecosystems to recognize and reward player achievements. These tokenized achievements can also become bragging rights on forums and social platforms, giving players unique statuses in their community.

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Pokemon League (Source: Youtube.com/@ObitoTube)


Through its customizable and interoperable NFTs, ERC-6551's TBAs allow for cross-game gameplay. The on-chain ownership feature of ERC-6551's TBAs provides for a more rewarding gaming experience. The on-chain verification function of ERC-6551's TBAs improves the motivation of gamers. In this manner, ERC-6551 is a game changer for Web3 gaming NFTs.