Xadhoom is a character from the PKNA comic series.
Xado (her original name) was one of the most brilliant minds on planet Xerba. When the Evronians came to Xerba, she believed they came in peace, but they devastated Xerba and enslaved its population (turning several of them into Coolflames). Xado, who wasn't captured, experimented on herself to become a powerful being and renamed herself Xadhoom (which means "creditor" in Xerbian, as she considers the Evronians owe her her home world).
Xadhoom met the Duck Avenger when fighting the Evronians on Earth and they have fought together several times. Donald sometimes tries to have Xadhoom not so obsessed on her revenge, and jokingly nicknames her "beauty eyes" due to her monochromatic green eyes.
After finding and freeing her people, Xadhoom sacrificed herself, using her energy to become a star to allow them to survive.
Xadhoom has some similitude to the Power Rangers character Magna Defender, as both are characters who are after the villains just for their personal revenge but end up fighting side to side with the main hero (Leo for Magna Defender, Donald for Xadhoom) who is fighting the same villain for a genuine sense of justice.