Miis can create the strongest being (spoilers for miitopia)

It's surprising simple In miitopia the dark curse when they possess someone can create monsters with powers stronger than their hosts and the curses power even combind. But in order to give the monster power they need a mii face. at the end of miitopia after facing the darkest lord the main character creates a new face for the dark curse to be reborn (aka the main character can create not only mii body's but mii faces) about 2/3 into the game you beat the dark lord and the dark curse trys to possess the main character and fail as the great sage sacrifice s themself creating the darkest lord but If the dark curse where to have possessed the main character the resulting fusion can create a monster or being stronger then itself and give it power through faces which sense the monsters created can have abilitys and other stuff then a loop of infinitly growing power can happrn where the fusion of the dark curse and main character can create a stronger monster or mii with the ability to create a stronger monster or mii which then can create a stronger monster or mii and so on.