Mettle Testers are people who are tasked with testing the strength and courage of others. They are often employed in situations where a person's character is being tested, such as in military or law enforcement training. The term 'METTLE testers' is derived from the word 'METTLE, ' which means courage and fortitude. The job of a METTLE tester is to evaluate the strength and courage of those they are testing, and to provide feedback on their performance. The term 'TRIALS' is often used to refer to the tests that METTLE testers administer.