Sersi is a member of the community of genetically-engineered Eternals who came to Earth. She was created alongside the other Eternals by the Celestials, and sent by Arishem the Judge to Earth in 5000 BC to protect the humans from the Deviants. While on her mission, she grew a close relationship with fellow Eternal Ikaris and eventually married him. In the 16th century, the Eternals finally wiped out the final Deviants but disbanded after when they realised their mission was over. Within the next few years Ikaris would go on to abandon Sersi and she moved to London with Sprite. As she waited for her next instructions from Arishem, Sersi grew to relish living amongst humans. By 2023, Sersi worked as a history professor at London's Natural History Museum and was in a relationship with her colleague Dane Whitman. However, she, Dane and Sprite were ambushed by the Deviant Kro who had the ability to heal. After reuniting with Ikaris, they discover their former leader Ajak dead and reassemble the Eternals to put an end to the new Deviant threat. They discover that Ajak had the ability to contact Arishem, and that he had sent them to Earth not just to stop the Deviants, but prepare for the arrival of the Celestial Tiamut, a process known as the Emergence. However, the Emergence would also result to wipe out mankind, so the Eternals decide to prevent it. They are then ambushed by the Deviants and the Eternal Gilgamesh is killed. They also learn that Ikaris betrayed Ajak to the Deviants and allowed them to kill her in order to stop her from preventing the Emergence. The Eternals battle Ikaris, who is joined by Sprite, and eventually she uses the Uni-Mind to destroy Tiamut. Guilty, Ikaris commits suicide while Sersi uses her powers to turn Sprite into a human, as she wished. Days later, she is abducted alongside Kingo and Phastos by Arishem, who seeks to review their memories in order to determine if Earth is worth sparing or not.