The protagonists are the X-Men, a group of teen-aged mutants: a subspecies of the human race, who possess latent super-human abilities from birth, due to the presence of the mysterious "X-Gene" within their genetic codes, which set them apart from the rest of humanity and despite being feared and distrusted by the general public and authorities, use their super-powers to prevent and stop unnatural threats to both the human and mutant race, while being mentored by Professor Charles Xavier, The X-Men's founder, a world-renowned expert on genetics and the world's most powerful telepath. The series features many characters and storylines similar to those of the original X-Men series. "Ultimate X-Men" almost completely ignores supernatural or mystical elements as plot devices, and the X-Men have no secret identities, and mutants are distrusted and hunted down. The series began in 2001 under writer Mark Millar and artists Adam Kubert and Andy Kubert, while the final issues of the series were written by Aron Coleite and penciled by Mark Brooks. "Ultimate X-Men" was met with considerable commercial success, even outselling most of the other X-Men comic titles and received a generally positive response from critics and readers, who praised the art-work by various artists, the writing runs of Millar, Bendis, Vaughan, Kirkman and Coleite, the character development and progression of the titular superheroes throughout the series and the unique and interesting twists on conventional X-Men themes and concepts, along with the fresh and distinctively modernized re-imagining of the classic X-Men mythos, while the uneven quality of the writing, the somewhat edgy and unnecessarily adult-oriented tone and direction of the comics and some of the changes and deviations from the original X-Men comics were singled out for criticism.