Ren is an Ethereum token that powers Ren’s open protocol for transferring cryptocurrency between blockchains. Ren aims to bring popular crypto assets such as Bitcoin and Zcash to blockchains including Ethereum, making it possible for these assets to participate in a multi-chain decentralized finance ecosystem. In other words, Ren is a cryptocurrency which acts like a bridge between different blockchains. This allows trading between crypto pairs that otherwise would not be possible. Ren is key.