A Watchtower Node is a specialized type of node in systems that use payment channels, like the Lightning Network. Its main purpose is to monitor the blockchain for specific transactions on behalf of users.When two parties open a payment channel, they create a multi-signature wallet that allows them to transact off-chain. To ensure fairness, each participant can broadcast their most recent transaction state to the blockchain if the other party attempts to cheat by broadcasting an outdated state.Watchtower Nodes act as third-party monitors. They watch the blockchain for signs of such cheating attempts and can step in to broadcast the latest valid state if necessary. This helps protect users who might not be online or actively monitoring their channels.By using a Watchtower Node, users can enjoy greater security and peace of mind, knowing that someone is looking out for dishonest behavior while they conduct their transactions more privately. This enhances the overall integrity and reliability of payment channels.