The Scarlet Witch (Wanda Maximoff) is a fictional character appearing in American comic books published by Marvel Comics. The character was created by writer Stan Lee and artist Jack Kirby. Her first appearance was in The X-Men #4 (March 1964) in the Silver Age of Comic Books. Originally said to have the ability to alter probability, the Scarlet Witch has been depicted as a powerful sorceress since the 1980s and was later said to be powerful enough to alter reality. For most of her comic book history, she is portrayed as a mutant, a member of a fictional subspecies of humans born with an 'X-gene' that grants superhuman abilities and traits. This was revised via a 2015 storyline establishing that her superhuman traits are a result of experimentation done by High Evolutionary when she was a child. Scarlet Witch is first depicted as a reluctant supervillain along with her twin brother Pietro Maximoff / Quicksilver, both founding members of the Brotherhood of Mutants. A year after her debut, she joined the Avengers superhero team and ever since has often been depicted as a regular member of that or related teams (such as the West Coast Avengers and Force Works). In 1975, she married her android teammate Vision, later using borrowed magical forces to make herself pregnant, resulting in twin sons William ('Billy') and Thomas. Stories in 1989 wiped Thomas and Billy from existence (they would later reappear as the heroes called Wiccan and Speed) and removed Vision's emotions, leading to his and Wanda's marriage being annulled. The character's in-universe backstory and parentage have changed more than once.