The Seal of the First Builders was a seal created by the First Builders at the end of the First Acrean War. It was located deep inside Acrea's moon, the Enemy's former base, and was designed to prevent the Enemy from emerging. It was composed of Power Crystal and pure crystalline Creativity, the latter coming from the essence of the First Builders themselves. Nearly 1 million year later, the Minifigures accidentally broke it and unleashed the Enemy, thus starting the New Acrean War.