Cosmic evil is connected with evil on a cellular level, and the children along with some new friends go within Charles Wallace in order to save his mitochondria (and the fictive entities living within them, the farandolae) from the un-namers—the Echthroi (the Ancient Greek word for "enemies"). The Echthroi are powerful, evil creatures whose desire is to X (i.e. extinguish, unname) creation. Author Calvin Miller writes that the Echthroi are "demonic spirits" that "are always stalking good, making the whole sick, the entire partial, the holy eroded by the contaminated." The Echthroi reappear in "A Swiftly Tilting Planet", trying to prevent Charles Wallace from reaching key moments in history in a bid to save the world from nuclear destruction.