The Deviants are a monstrous and apex race of near-immortal beings genetically engineered by the Celestials to ensure the development of sapient life on the planets seeded with nascent Celestials by wiping out the planet's apex predators. However, due to their biological nature, the Deviants evolved and began to hunt and wipe out all life. To protect the sapient life required for the Emergence of a new Celestial, Arishem then created the synthetic Eternals and sent them to eliminate the Deviants.