From Cassius Comics

Real Names: Celeste, Mindee and Phoebe (last name unknown). Formerly Esme and Sophie (both deceased).

Identical quintuplet mutants, Celeste, Esme, Mindee, Phoebe and Sophie enrolled in the Xavier Institute for Higher Learning, where they quickly became the proteges of fellow-psychic Emma Frost. The sisters suffered tragedy when Sophie died from an overdose of the drug Kick and the stress of using Cerebra while repulsing Kid Omega's takeover of the Institute; things also became strained between them and Frost when she began a psychic affair with fellow-teacher Scott Summers (Cyclops). Esme soon began acting against the group, mentally forcing Institute student Beak to shoot Frost, shattering her diamond form. Frost was saved by Summers' wife Jean Grey (Phoenix IV), and Esme left the Institute. The remaining sisters blamed Frost for the events, and got their revenge by revealing Frost and Summers' affair to Grey. Esme soon resurfaced as a part of the Brotherhood of Evil Mutants, led by Xorn, who was posing as Magneto. Esme attempted to seduce "Magneto", but he dismissed her as being a mere child. Esme soon saw him for the madman that he was and joined the fight against Xorn/Magneto, but he killed her during the battle. The remaining sisters continue to study at the Xavier Institute, although for the most part they have shunned their former mentor Frost.

The Stepford Cuckoos (as the sisters are collectively known) are powerful telepaths, and their minds are constantly linked. They often speak in unison, but they do function independently of one another, and are fully capable of independent thoughts and actions. In a possible alternate future, Celeste, Mindee and Phoebee have been seen to have taken on the name "the Three-in-One".

Note: The Stepford Cuckoos likely took their name by combining the title of Ira Levin's novel "the Stepford Wives" and the characters of the Midwich Cuckoos from the film "Village of the Damned", though this has never been confirmed.