Ms. Steed, in the mainstream reality (Earth 616), was a member of the London Branch of the Hellfire Club. She was the Black Queen of their Inner Circle, only out ranked by Shinobi Shaw, their Black King. She was on a mission from both Onslaught and Blackheart to attempt a coup and take over the London branch.
Sebastian Shaw, of the American branch Hellfire Club, had sent Captain Britain to the London Branch to find out what was going on. Captain Britain was a member due to his lineage,. Ms. Steed had been successful in killing Shinobi Shaw after he went insane. Shorty after, she was engaged by Captain Britain. She attempted to use her formidible psionic gifts against him, only to have them reflected back toward her. He nearly take her head off, effectively incapacitating her.
Her current whereabouts are unknown, she is most likely among the thousands of mutants depowered post-decimation and she is in jail for her crimes that she committed, though neither of these facts have been confirmed.
Ms. Steed was created by Carlos Pacheco. Her AoA counterpart was created by both Warren Ellis and Ken Lashely.
Ms. Steed has a very rare form of telepathic power that she calls Psionic Skinning and she is Immune to telepathic intrusion.
Ms. Steed is a telepath with the unique mental ability to create blades of pure psionic energy. She wields these blades to attack and disable her foes. These blades allow her to do a number of things such as: warping the minds of her opponent, ingiting pain sensors, destroying physical portions of their brain, and destroying psionic forms or astral projections.
As a result of her powers she is funcationally immune to any type of psionic or telepathic attack of any form. Her very presence is absolutely destructive to telepaths and their astral projections.
In the Age of Apocalypse, Ms. Steed is known as Damask. Here she is an elite assassin in the employ of Apocalypse. She is also the leader of the deadly trio known as the Pale Riders. Rounding out the trio are Danielle Moonstar and Dead-Man Wade. Her past is largely unknown. She first appears as a student/apprentice of the Shadow King. He trains her in the skillful, deadly use of her mutant powers. While under the Shadow King's tutleage, he becomes very sexually attracted to Damask. In a short time, she rises to become a trusted, high rank assassin for her Lord Apocalypse. Due to this he chooses her and her Pale Riders to seek out and locate a place called Avalon. He wishes for her to destroy both Avalon and those who live there. Without question, she accepts the mission, and heads out.
En route to their first stop, Damask's patience is tested greatly by her team. Danielle is torturing Dead-Man Wade by slicing his skin and watching it regrow. Damask tells her once to stop, but Danielle doesn't. Damask replies by killing her and taking great joy in doing so. They finally locate and arrive at Avalon. But something stops Damask. She has never seen such beauty nor such peaceful people. Consumed by her thoughts, Damask begins to doubt her mission. How could she destroy something so beautiful? Dead-Man Wade is not held back as he immediately attacks the residents of Avalon. However, unknown to the evil duo, Nightcrawler arrives on his own mission and fights Wade to a stand still. It is here that Damask makes her decision to desert Apocalypse's way. Instead she joins Nightcrawler's ragtag, AoA version of Excalibur, which includes Mystique, Destiny, Douglas Ramsey, and Switchback. Before they leave a last battle occurs between them and the Shadow King. In the end Douglas Ramsey dies saving his team and Shadow King is slain as well. Once free, they continue on with their mission. Damask is not mentioned in the 10th anniversary AoA story. Her whereabouts are unknown. It is also assumed that this version of Emma Steed was depowered post decimation, though this also isn't confirmed.