Chaos is a "Second-Generation Angeloid, Type Epsilon" (第二世代エンジェロイドタイプεDainisedai Enjeroido, Taipu Epushiron?) and a major antagonist of the series. She initially appears to Tomoki as a girl in a nun's outfit. Chaos can change her appearance to mimic someone dear to her victim in order to instill turmoil and confusion (as her name implies), as she did against Nymph (and Ikaros) by taking on the likeness of Tomoki. Her "wings" are a wicked array of bladed, almost organic-like appendages. Unlike the first generation Angeloids who lack the ability to sleep, Chaos can enter another person's dream, as she has initially done with Tomoki. Chaos has a strange obsession with love, often asking the person what love is, to which Ikaros responded that love, for her, was a sensation of pain in her reactor, obviously in a figurative sense.
Chaos's first mission is to retrieve Ikaros's core. She lures Nymph by deceptively posing as Tomoki and then orders her to kill herself. She also fights and defeats the other first generation Angeloids, except for Ikaros who sends Chaos into an ocean chasm where she was temporarily incapacitated due to the great water pressure. While there, she concludes that love equates to pain. Chaos was left in the abyss, where she dismembers and devours fish to "grow bigger" and "to show her 'love' to everyone". She easily devours Seiren, one of the Sky Master's Angeloids, and uses the Pandora program to evolve into Chaos Version 2. She continues to question love by following Tomoki around a bit, but returns to her master only to be shot down by the Zeus cannon, and after overhearing Tomoki tell his Angeloids to go away, decides to return to the ocean floor to express her love more. She later returns to devour the dark Angeloids; she acquires their powers, yet holds back from attacking Tomoki because of her feelings for him, and her desire to be accepted by him as a "good girl". She returns to the ocean floor as Astraea looks for her.
In the Sora no Otoshimono: Forte anime, after Chaos is plunged into the sea, she emerges as an adult and fights Nymph and Astraea; she easily overpowers them, until Ikaros arrives. She was later defeated by Astraea and Ikaros, who use their upgraded weapons (courtesy of Nymph) and briefly shuts down, after which Tomoki installs on her chain a padlock device given to him by Daedalus, who then restores Chaos to her child form. Chaos then joins the cast as the newest resident of Tomoki's household.
