Ajak was the wise and spiritual leader of the community of genetically-engineered Eternals who came to Earth.
Created by the Celestials in the World Forge, Ajak was sent to Earth in 5,000 BC to progress the planet's societal development, and protect it from the Deviants. Ajak was aware of her purpose in life to pave the way for Earth's Emergence with the birth of Tiamut.
However, she was inspired by the heroics of the Avengers during the Battle of Earth, and instead opposed the ideals of her creators, believing humanity was worth saving.
Although having confided her opposition to Ikaris, she was ultimately betrayed by him and lured to a pack of Deviants in Alaska for her to be murdered.