To unlock the Brutal End trophy in Mortal Kombat 11, you will need to perform 25 Brutalities. There is a second trophy available for performing 100 Brutalities:
The quickest way to unlock this trophy is to set the number of rounds to 1 in the game settings and then fight either against a second controller or against the AI on Very Easy difficulty.
Take down your opponent's health until they have very little remaining, and then with the last hit, perform an uppercut by pressing
and holding
.
Retry and repeat until the trophy unlocks.