Cecilia Reyes is a doctor who specializes in trauma surgery, and she is a mutant that can project a forcefield around her body that protects her from attacks. She can expand the field to protect others, use it to push people away, and even mold it into spikes to use as a weapon. Cecilia was introduced in X-Men #65 (June 1997) by creators Scott Lobdell and Carlos Pacheco.

She grew up in the Bronx and decided to become a doctor after her father was shot in front of her and she couldn’t save him. When her mutant powers were discovered, the X-Men asked her to join the team, but she had no interest in being a superhero, preferring to focus on trauma surgery. That changed when she was targeted by the anti-mutant task force in Operation: Zero Tolerance. Looking to protect herself and other mutants, she joined Iceman to help people escape New York City and find the leader of the taskforce. She also saved Pyro from a gunshot wound using both her medical knowledge and mutant powers to protect herself from his heat.

It was then that Cecilia joined the X-Men, and her first mission involved saving Cyclops from explosive nanotechnology threatening to kill him and anyone nearby. She joined them to fight Neo, a group of mutants who considered themselves to be more evolved than other mutants. During that event, Cecilia was trapped in Neo’s stronghold beneath New York and used the power-enhancing drug Rave to break free.

Cecilia was captured and held at the mutant concentration camp known as Neverland. In the dire situation, she tried to help other captives by administering medical aid to those who needed it. The story ended with Cecilia supposedly killed by a brainwashed Agent Zero, until a future story revealed that she had survived and was volunteering at homeless shelters.

Eventually, Cecilia rejoined the X-Men and worked with Psylocke to find one of the Five Lights. She treated Gambit for injuries he had sustained in battle, and then when an earthquake hit New York, the pair rescued people and she treated the injured. During Fear Itself, Cecilia helped the X-Men against Juggernaut by protecting a group of anti-mutant protestors from being attacked. Then she joined the mutant community on Krakoa where Cecilia became an expert in mutant biology and ran medical operations or the residents.