Fire Emblem Three Houses: Antagonists
Named Nightcrawler, they seem to be pulling the strings, or at least enjoying the wars between the 3 houses during the second part of the game. Fire Emblem being generally quite Manichean from this point of view, it is to be expected that they will be very wicked and that they will want to awaken an ancient evil in order to rule the world, or something of that nature. You will have the opportunity to face some of them from the first part of the game.