Ronin is an Ethernet side chain specially built for Axie Infinity, a POA network operated by verifiers appointed by Sky Mavis, the core development studio of Axie Infinity. The block needs to be approved by 2/3 of the verifier. The verifier is responsible for writing and validating blocks, updating the price language machine, and handling the storage and transfer of assets (ETH, ERC20, and ERC721) to and from Ronin.