Cloud, or Jane Doe as she was called, had no memory of her childhood, her family or even her real name. On November 1, 2003 she was discovered wandering alone and naked on a highway and confined to a mental institution for the interim. Leonard Samson discovered her there and decided it was no place for a young mutant and arranged for her to be transferred to Xavier's School for Gifted Youngsters.
Jane settled quickly into the school and made many friends. Her roommates were Amanda Sefton and Paige Guthrie, both of whom were protective of the extremely naive older girl. She got involved with the Red X program and assisted in the evacuation of Stonewall Farm. She began a relationship with Bobby Drake, although he was frequently absent at this time. The kidnapping of many of the students, including her two roommates to Asgard was extremely traumatic for the girl who had no memory of having friends before.
In December 2005 Jane left the school to try and discover more about her identity.
Jane has the ability to transform herself into a small cloud. As a cloud, she is primarily composed of hydrogen and helium and contains no significant amounts of oxygen. She can suffocate people by engulfing them in her oxygen-less cloud form. She can emit lightning-like electrical discharges, but she cannot produce rain. In cloud form, Jane can also separate into smaller clouds while her consciousness maintains control over all of them. Jane can move about in her cloud form even when there is no wind by mentally redistributing partial pressures within herself. Also while in cloud form, she can mentally project her thoughts into other people's minds so that she can communicate without a speech apparatus.
Jane doesn't like clothing. In fact, if not reminded constantly, she'll just not wear clothes. She can generate a constant mist of cloud-stuff around herself for modesty, so she doesn't see the point of wearing them.