> ## Documentation Index > Fetch the complete documentation index at: https://docs.fantasytier.com/llms.txt > Use this file to discover all available pages before exploring further. # Results provider (Oracle) > Reality.eth and Kleros oracle design with Merkle roots. Fantasy Tier leverages **Reality.eth** as a crowdsourced oracle, reinforced by **Kleros** as the arbitrator, to ensure a transparent and trust-minimized way of determining fantasy scores. ### How Reality.eth Works Reality.eth operates as an on-chain Q\&A oracle where users can post questions and stake deposits to provide answers. If someone disagrees with a posted answer, they can challenge it by submitting a new answer with **double the previous deposit**. This mechanism creates an exponentially increasing cost to modify a response, making dishonest behavior financially unviable. To ensure accuracy, Reality.eth also allows for arbitration by an external dispute resolution system. In Fantasy Tier, **Kleros Court** serves as the final adjudicator. If a challenge escalates to Kleros, jurors review the case and issue a binding decision, securing a fair resolution. Simplified flowchart of Fantasy Tier oracle design *Simplified flowchart of Fantasy Tier oracle design* ### Adaptation for Fantasy Tier Unlike traditional implementations where individual event outcomes are reported directly, Fantasy Tier optimizes this process by using **Merkle trees**. Instead of submitting answers for each player's performance separately, Reality.eth will only store a **Merkle root**, which serves as a cryptographic commitment to a dataset containing all players' scores. This approach: * **Reduces gas costs**, as only a single hash (Merkle root) is stored on-chain. * **Increases efficiency**, allowing bulk verification of fantasy scores in a single transaction. * **Maintains verifiability**, as anyone can reconstruct the Merkle tree off-chain and confirm its correctness. ### Arbitration by Kleros If a dispute arises regarding the reported Merkle root, Kleros can be called upon to rule. Jurors will evaluate the correctness of the reported data, ensuring that the fantasy game results are fair and resistant to manipulation. By integrating **Reality.eth and Kleros**, Fantasy Tier achieves a decentralized, tamper-resistant, and cost-effective oracle system, ensuring that player scores reflect real-world performance without reliance on centralized entities.