> For the complete documentation index, see [llms.txt](https://docs.zyfi.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.zyfi.org/integration-guide/case-studies/case-study-mithraeum.md).

# Case Study: Mithraeum

<figure><img src="https://lh7-rt.googleusercontent.com/docsz/AD_4nXej29Ezkqc0_cpjXAKGjFF3UofCGFVEzlvxGeuZ9Jvz8Z4JklBlmev394YdOOHaV6WVueX7hUZU3zMkT3-sW295H4YNbtgBHhfbaj-6_sUk9uMR3vFpIKC2PmTKsAlUHHhCPVrzmT-PTnbqtm0scOFqyMLa?key=LfmIHxG_TrGqrDYMcbnfQA" alt=""><figcaption></figcaption></figure>

## What's Mithraeum?

[Mithraeum](https://mithraeum.io/) is a fully decentralized, real-time strategy game recently launched on ZKsync, incorporating core blockchain principles like decentralization. In Mithraeum, players are immersed in historical periods, participating in large battles, sieges, and alliances on a unique world map.&#x20;

The game is supported by prominent blockchain partners, including **Gnosis Chain**, **Arbitrum,** **ZKsync**, and is dedicated to maintaining decentralization while allowing community contributions to its development.

Despite its decentralization, Mithraeum faces a significant challenge: **gas fees**. Every action performed on-chain requires a transaction, leading to frequent gas fee payments that can disrupt gameplay and diminish the user experience. Users often encounter numerous MetaMask pop-ups to approve transactions and pay gas fees, which **detracts from the game's immersion** and appeal.

## Zyfi: Paymaster on ZKsync

Zyfi offers a solution to these issues on ZKsync. By leveraging ZKsync’s native Account Abstraction (AA) and [Zyfi's sponsored paymaster](/integration-guide/paymasters-integration/sponsored-paymaster.md), Mithraeum users can avoid gas fees entirely, providing a smooth, uninterrupted experience. Zyfi's paymaster smart contracts cover the gas costs for users' transactions, allowing Mithraeum to deliver a seamless gaming experience without frequent interruptions for gas payments.

As part of the launch initiative, Zyfi has sponsored **20,000 gas-free transactions**, equivalent to **$2,000 worth of gas**. This initial funding ensures that early Mithraeum users can enjoy the game without worrying about transaction costs, thereby boosting adoption and engagement within the Mithraeum ecosystem.

<figure><img src="/files/rkyJbB1eb8p2K0MzSnLD" alt=""><figcaption><p>Overview of the Mithraeum on-chain game.</p></figcaption></figure>

## UX/UI Implementation and Sybil Prevention

The UX/UI implementation time depends on the design choices. As a gaming platform, Mithraeum decided to use the [sponsored paymaster:](/integration-guide/paymasters-integration/sponsored-paymaster.md)

* **Full Sponsorship:** They chose to cover 100% of gas fees for users to ensure a seamless experience.
* **Sybil Prevention:** To prevent Sybil attacks, they implemented a credit system per address, allowing each user to enjoy a certain number of free transactions.
* **UI Update:** A simple checker (see image below) at the beginning of the game was added to let users choose if they want to enjoy free transactions or not.

The UX/UI implementation for Mithraeum took around 1 development day to complete, with sybil prevention being one of their biggest concerns. The credit system for each address was an effective method to offer the best on-chain gaming experience while preventing Sybil attacks.

<figure><img src="https://lh7-rt.googleusercontent.com/docsz/AD_4nXeuqyeK9erh1lhnOgx35JA2PihV29TYGE9PsKebGo3yV2t89FveV9AxmgIRxVXSlDAwXHicmomE-cmN58A9hrbbcp3iYejEHFv84ztP0SLfmd0knKwMpRDsmv_QDsdVK_njljx1blofh0q-JlnuCo-eL7sY?key=LfmIHxG_TrGqrDYMcbnfQA" alt=""><figcaption><p>Onboard Step into the Mithraeum game where users can decide to activate gas-free fees.</p></figcaption></figure>

### Conclusion

The integration of Zyfi's paymaster solution into Mithraeum significantly enhances the user experience by eliminating gas fee interruptions, addressing one of the major barriers to on-chain gaming. This approach also allows Mithraeum to remain committed to its decentralized principles while offering a **smooth and engaging experience.**&#x20;