Why Your NFT Sword Can't Walk Into Another Game (Yet)

Picture the pitch, because you've probably heard it. You win a legendary sword in a fantasy RPG. Next week you log into a sci-fi shooter, and there it is, glowing on your back. Then you take it into a racing game as a hood ornament. Your items, your history, everywhere you go.

This idea, usually called interoperability, was one of the most repeated promises of the 2021 NFT boom. It sounded like the natural next step: if your sword is a token on a public blockchain, any game can see that you own it. So why, years later, is a sword that walks between games still almost entirely a demo?

The short answer: the blockchain solves the easiest part of the problem. Everything else is hard.

The part blockchains really solve

A blockchain is very good at one thing here. It gives every game the same, public, tamper-proof answer to the question "Who owns token 4,812?" Without it, two games from different companies would need to trust each other's databases, sign contracts and build an integration. With it, any developer can check ownership for free.

Gaming chains lean on this. Japan's Oasys advertises "cross-game NFTs". Immutable's Passport wallet gives players a single identity across the hundreds of games on its network, so a studio can see what a player holds elsewhere.

So far so good. But knowing someone owns token 4,812 tells a game almost nothing about what to do with it.

Problem one: the art

A sword in a stylised mobile RPG and a sword in a photorealistic shooter are made in completely different ways: different polygon counts, textures, rigs, animations and lighting. You can't simply drop one game's 3D model into another and expect it to look right, or even to load.

The industry has been working on shared formats for years. glTF, from the Khronos Group (the body behind OpenGL and Vulkan), is often described as the "JPEG of 3D", a common way to package 3D models. It helps. But a common file format is like a common language: it doesn't make a cartoon character fit into a war film.

In practice, if a second game wants to honour your sword, its own artists have to make their own version of it. That's real work, paid for by a studio that didn't sell you the item.

Then comes balance. Now the sword is in the second game. How much damage does it do?

If it's powerful, players who bought it elsewhere get an advantage nobody else earned. If it's weak, its owners feel cheated. Every competitive game guards its balance closely, because balance is what makes it fun. Importing items designed by someone else, for a different game, is a balance designer's nightmare.

That's why most real-world experiments stick to cosmetics: items that change how you look, not how you play. Even then, a glowing aura that looks fine in a cartoon world can ruin the mood of a horror game, so studios still want the final say.

Problem two: the business

This is the biggest obstacle, and the least technical. Game companies make money by selling items. If players can bring free swords from elsewhere, why would they buy yours? A studio honouring another company's items is doing extra work to lose sales.

There are also licences. Many cosmetics are tied to deals with film studios, sports leagues or musicians, and those contracts specify exactly where the likeness can appear. A Marvel hero skin licensed for one game can't legally wander into another just because a token says so.

Then there's support. If a player's imported sword glitches through a wall in your game, who fixes it: you, or the studio that made the original? If the item is later found to have been stolen, which game's rules decide? Every one of these questions needs a contract, a support process and somebody's time, none of which a blockchain provides.

So the cases that work tend to be either inside one company or between partners with a deal.

Who is actually closest

Ironically, the most convincing example of items crossing between game experiences comes from a company with no interest in blockchains.

In December 2023, Epic Games launched LEGO Fortnite, a survival-crafting game inside Fortnite, along with new racing and music modes. Many of the outfits players had already bought could be used across these modes. Cars from Rocket League, another Epic game, also turned up in Fortnite's new racing mode.

No tokens were involved. It worked because one company owned the games, the art pipeline, the balance and the store, and decided to make it happen. That's the real lesson: interoperability is mostly a coordination problem, and it's easiest when one party controls everything.

On the blockchain side, the most interesting experiments came from the bottom up. Loot, a 2021 project, gave out 8,000 "bags" that were simply lists of item names, and invited anyone to build games around them. Some did. It was creative, but it also showed the limit: a list of words is easy to share, while a usable game item is not.

What a realistic version looks like

If interoperability arrives, it probably won't look like the swords-everywhere fantasy. More likely:

• Badges and history that follow you: achievements, ranks or proof that you were an early player, which other games can reward with their own items.
• Partnered cosmetics, where two studios agree to honour each other's items and each makes its own version.
• Shared identity: one wallet or account that lets games recognise you, as Passport does across Immutable's network.
• Within-family items across a publisher's own games, on or off a blockchain.

By the numbers

• 2018: ERC-721, the main NFT standard, is finalised; it defines ownership, not appearance
• June 2022: the Metaverse Standards Forum launches
• Dec 2023: LEGO Fortnite and new modes bring shared outfits across Fortnite experiences
• 8,000: Loot bags released in 2021 as building blocks for others' games

WGC's take, and what to play next

The blockchain part of interoperability works. Everything that makes a game a game, the art, the rules, the economics, the licences, still has to be negotiated by people. When you next see a project promising items that travel between worlds, ask three questions: Which games have signed up? Who makes the art in each? And what does the item actually do there? If there are no clear answers to all three, it's a slogan, not a feature.

For more on what owning a game item really means, read our explainer Do you really own that NFT sword?, and for the bottom-up experiment, our story on Loot.