Soseh Mykros is the genetically engineered daughter of Dr. Anatol Mykros, one of the leaders of the Council, a globe-spanning underground organization which, one dedicated to eradicating pollution, overpopulation and racial/territorial conflict, now seeks nothing less than world domination.
Dr. Mykros raised Soseh and her fraternal twin, Ellina, to adulthood in virtual-birthing chambers. The sisters were subjected to thousands of medical experiments and tests, designed to transform them into the Council's best assassins. But Soseh revealed the truth about the Council's true plans and rejected her father and the Council, while Ellina stayed on her father's side.
Soseh came into conflict time and again with Ellina; she disrupted the Council's activities whenever she could, and eventually killed her sister in battle. With the help of the JSA, she has done a considerable amount of damage. Dr. Anatol Mykros has yet to be found.
Soseh was seen battling on the JSA's side during the Princes Of Darkness storyline, but soon after this she joined Black Adam's team consisting of Alex Montez, Atom Smasher, Brainwave Jr. and Northwind. During their time in Khandaq, she became romantically involved with her teammate, Alex Montez, but was accidentally killed by him.
Along with superhuman strength, speed and healing, Soseh has "eidetic kinesthesia" - the ability to instantly mimic any physical skill or fighting style. She has already absorbed the brawling tactics of Wildcat, the martial arts of Black Canary, the gymnastics of Star-Spangled Kid and the swordplay of Ellina.