Not much is known about the woman that became known as Dark, including her real name. The terrorist organization known as the Undertow implanted an neurochip into her body. She has basically been brainwashed and is forced to fight with other brainwashed superpowered individuals in the group known as the Soldiers of Misfortune.
The Soldiers of Misfortune went up against the New Warriors after some Air Force soldiers were killed by the Soldiers in Africa. The Soldiers of Misfortune weren't prepared to take on the Warriors and were defeated. The Soldiers managed to escape custody when there were teleported back to their base by their leader.
Dark and the Soldiers of Misfortune have not been seen since.
Dark was created by Evan Skolnick and Richard Pace in 1994 and first appeared in New Warriors # 54.