The growing fragmentation of the blockchain ecosystem has intensified the demand for secure and scalable interoperability protocols. Existing cross-chain solutions face an ‘interoperability trilemma’, struggling to simultaneously achieve decentralization, security, and scalability amidst a fragmented blockchain ecosystem. This paper introduces Acheron, a market-based multi-relay architecture designed to navigate this trilemma by decoupling security from a single monolithic entity and parallelizing message transport across independent, sovereign Relay Chains. Each Relay Chain operates as a self-contained Proof-of-Stake (PoS) network with slashing-based cryptoeconomic security, eliminating monolithic bottlenecks. Routing decisions are governed by a Multi-Attribute Utility Theory (MAUT) model that dynamically optimizes for security, latency, and cost, while the Acheron DAO and Watchtower Network ensure verifiable governance and continuous relay telemetry. Experimental validation using the Hardhat framework and the Base Sepolia testnet demonstrates that throughput scales linearly from 0.13 to 1.27 transactions per second as relays increase from one to ten, while latency variance decreases by over 90 % and average transaction costs remain stable. Compared with established baselines, Acheron achieves a 7 % reduction in mean latency and over 2.2 × higher throughput under identical workloads. These results demonstrate that Acheron’s market-based paradigm presents a viable and quantitatively superior path toward achieving secure, scalable, and decentralized interoperability for both financial and IoT-driven ecosystems.
