I needed stronger test subjects to progress my experiments to the next level.A strong will, strong body, and even a strong soul! That's when I...The humans who couldn't withstand its power died, and they became Vicious Minds.TapAfter that, they lost all their memories and consciousness, reduced to empty shells of their former selves. ran into you, as if it was meant to be.I was able to create 'cores', smaller versions of the appropriated hearts of Ymir.