Trillions of years prior to the events of the series, Bill Cipher originated from the second dimension. Bill, however, despised living there, describing it as a dimension of "flat minds in a flat world with flat dreams. He liberated his dimension by burning it along with everyone he's ever known, including his own parents. He eventually took over a boiling, shifting intergalactic foam between dimensions—a lawless, unstable crawl space known as the Nightmare Realm. However, due to the Nightmare Realm's lawlessness and lack of any consistent physics or rules, it was fated to eventually self-destruct. After coming to learn of a prophecy that stated he could merge the Nightmare Realm with the third dimension, Bill manipulated countless humans over the eons so he could become a physical being and liberate that dimension as well.