In proof-of-stake (PoS) and some delegated proof-of-stake (DPoS) blockchain networks, validators take on the role of verifying transactions and maintaining the network's integrity. They achieve this by proposing new blocks of transactions that are then validated by other validators in the network. To operate as a validator, an entity must stake a certain amount of cryptocurrency, which serves as collateral and incentivizes honest behavior. Validators are crucial for network security, decentralization, and the overall functionality of the blockchain.