D'Elise lived a life no different than a commoner until the defeat of the military dictatorship of the Erusean Republic by ISAF in the Continental War. ISAF restored the monarchy as a new government, making her father king and herself a princess. With the outbreak of the Lighthouse War, D'Elise became known for her defense of her country's offensive war, claiming that the International Space Elevator was a violation of Erusea's national sovereignty as well as publicly denouncing Osea's actions during the conflict, claiming that the country attacks indiscriminately and has injured many civilians.
- Princess D'Elise's name has French origins. In particular, her middle name, "Cossette", is an alternate spelling of "Cosette", best known as the name of the heroine in Les Misérables.