Fixx is a fictional mutant character in the Marvel Comics Universe from an alternate future. She as a member of X-Factor, X.S.E. and X.U.E. She first appeared in X-Factor (1st. series) #140. Fixx was created by Howard Mackie.
When Shard, a former X.U.E. member who had been transported to the main Marvel Universe by her brother Bishop in holographic form, became anchored in Polaris' body following Sabretooth's escape from US government custody, this allowed her teammates to follow her. Fixx was able to use her telepathic power to lock on to Shard and psychically transport herself and her teammates to our time, implanting themselves in recently deceased host bodies with the mission of preventing their future from occurring.
One thing that the group did was hunt down a man from their timeline named Micah—just a child in our time—and attempt to stop him from becoming the madman who helped kill mutants and who killed Greystone's mother. Greystone believed that the boy must be killed in order to stop his tyranny, but Fixx and Archer tried to convince him that it was unethical to judge a man for a crime they did not yet commit. After stopping him, the trio decided to join with X-Factor, but their tenure was short-lived.
Greystone slowly developed temporal insanity, believing that his mission was accomplished, and he could go home to a better world and be reunited with his mother, who might theoretically be alive. In an attempt to return to his own time, Greystone built a flying time machine, but due to shoddy craftmanship and unsound theories, the craft exploded, seemingly killing Greystone and Havok, who was attempting to stop him. With Archer's retirement and Greystone's demise, Fixx is the sole survivor of the X.U.E., but she may still continue to fulfill their mission in some way. It is unknown if Fixx retained her mutant powers during the M-Day.