Ammit was an ancient Egyptian demon who devoured the souls of the dead if they did not follow the principles of Ma'at, which represented justice, truth, and order. Whether they did or didn't was determined by weighing their hearts against the feather of Ma'at after they died. If the heart of the dead was heavier than the feather, Ammit consumed it, and the soul was destroyed. If it was lighter, the dead soul could continue its journey in the Duat, the Egyptian underworld. Ammit's name (ˤmmt in Egyptological transliteration) literally means 'devourer'.
"He hath not committed any sin, and he hath done no evil against us. Ammit shall not be permitted to prevail over him."