No Rest for the Wicked

Hidden, and the villain ending. A Grand Objective (1.0 endgame) - mutually exclusive with the other five, so do it on its own save.

You first have to reach 100% Infamy for Absolute Villainy - that is what unlocks the Tyrant Overlord objective to accept. Completing the objective is what earns this. The exact steps aren't documented publicly yet (the devs only say "survive the consequences of your actions"), so follow the in-game objective log; I'll fill in the specifics once they're confirmed rather than guess.