Mafia III

This achievement, as well as "Trust," is missable depending on how you treat your relations with the three Underbosses throughout the course of the game. In order to reach the Loyal state with an Underboss, you will need to assign them at least three districts. Since there are a total of nine districts in the city, you'll want to make sure they are evenly distributed between Burke, Cassandra, and Vito.

In addition to this, you will also need to complete each of their respective five-part side missions: "IRA Don't Ask" for Burke, ".45 in My Hand" for Cassandra, and "I Need a Favor" for Vito. Once these requirements have been met, you will reach the Loyal state with all three Underbosses and this achievement will unlock.