Elysius

Part 1: The Dossier: An At-a-Glance Summary

1)
Her name is a direct reference to the Elysian Fields, or Elysium, of Greek mythology. In mythology, Elysium was the final resting place for the souls of the heroic and the virtuous—a beautiful and peaceful paradise. This is deeply symbolic of her role as Mar-Vell's love and her presence at his peaceful death.
2)
Elysius's first appearance was in Captain Marvel #59 (Nov. 1978), and her death occurred in Guardians of the Galaxy (Vol. 2) #21 (Feb. 2010).
3)
The nature of her “artificial” creation has been depicted with some ambiguity. While called a “replicant,” she is a fully biological being with her own consciousness and free will, essentially making her a genetically-engineered test-tube baby, albeit a very advanced one based on the Eternal template.
4)
Despite being created by ISAAC, her “genetic father” is effectively Mentor (A'lars), as he was the creator of all life on Titan and the source code from which she was designed. This makes her, in a sense, the “sister” of Thanos, though this relationship has never been explored in the comics.
5)
The common misspelling of her name is “Elysius,” which aligns more closely with the mythological spelling. However, the official Marvel Comics spelling is Elysius.