Mutants — also known as "homo superior" — are an offshoot sub-species of humanity who are born with genetic abnormalities which grants them abilities, an appearance, or powers beyond the normal variation expressed in the human genome. While their appearance, abilities, and attitude towards their evolutionary cohorts varies widely, all Mutants possess the so-called "X-Gene" which expresses itself around puberty and causes the individual mutant's powers to emerge. Mutants have been been the victims of considerable persecution throughout their history on earth.