First Appearance: Invaders #15 (March 1977).
Appearances: Invaders #14-15.
Years Active: 1942-?
Ghost Girl, who was never given any other name, was one of the Crusaders. Like the rest of the Crusaders, the Spirit of '76, Captain Wings, Dyna-Mite, Thunderfist and Tommy Lightning, she was contacted by by "Alfie," a German spy posing as a Brit, and convinced by Alfie that the Invaders were actually German agents pretending to be Allied superheroes. The Crusaders clashed with the Invaders, as Alfie had planned, but Alfie's ruse was discovered and he was captured.
Neither Ghost Girl nor any of the other Crusaders, save Dyna-Mite, have appeared since then, so that we do not know if Ghost Girl survived the war. She had no powers, her ability to project an image of herself coming from equipment she was given by Alfie. When Alfie was captured, the Crusaders whose powers came from equipment (Ghost Girl, Captain Wings, Thunderfist and Tommy Lightning) abandoned that equipment. No other origin was given for Ghost Girl, nor has she ever appeared again, so it's unknown whether she even survived the war or whether she continued adventuring as a hero.
Note: Ghost Girl and the other Crusaders were, of course, part of the unofficial Marvel-DC crossover of 1976, where the Invaders fought the "Crusaders," a team whose members had the same powers as DC's Freedom Fighters, and where, in the pages of Freedom Fighters, the Freedom Fighters fought the "Crusaders," who had the same powers as the Invaders.