The umpire's assistant off the field in cricket is called the Third Umpire. The Third Umpire is responsible for making decisions using technology, such as TV replays, ball-tracking, snickometer, and Hawk-Eye, to assist the on-field umpires. They primarily help in reviewing close decisions like run-outs, stumpings, catches, and boundary checks.
Additionally, there is a Match Referee off the field who oversees the overall conduct of the game, ensuring that it adheres to the rules and spirit of cricket.