[Keeping the Peace] is an achievement in the Elder Scrolls Online, it is part of the Deadlands DLC. It can be completed in Fargrave. You should head to the Shambles. In there you can find three bosses that need to be killed in order to complete this achievement.
Boss Kezo
Boss Kezo can be found just north of the entrance to the Outlaw Refuge. He is standing on the upstairs level overlooking the area where the entrance to the refuge is.
Enzir of the Vanquished
Enzir can be found on the upstairs level as shown on the map. He is standing on a wooden platform that has some furniture on it.
Shaermeta
Shaermeta can be found on the upstairs level, she spawns infront of a little kiosk stand full of lanterns.