Ultimate X-Men is a superhero

Superhero

A superhero is a type of stock character, possessing "extraordinary or superhuman powers", dedicated to protecting the public. Since the debut of the prototypical superhero Superman in 1938, stories of superheroes — ranging from brief episodic adventures to continuing years-long sagas —...

 comic book

Comic book

A comic book or comicbook is a magazine made up of comics, narrative artwork in the form of separate panels that represent individual scenes, often accompanied by dialog as well as including...

 series that was published by Marvel Comics

Marvel Comics

Marvel Worldwide, Inc., commonly referred to as Marvel Comics and formerly Marvel Publishing, Inc. and Marvel Comics Group, is an American company that publishes comic books and related media...

 from 2001 to 2009. The series is a modernized re-imagining of Marvel's long-running X-Men

X-Men

The X-Men are a superhero team in the . They were created by writer Stan Lee and artist Jack Kirby, and first appeared in The X-Men #1...

 comic book franchise as part of its Ultimate Marvel

Ultimate Marvel

Ultimate Marvel is an imprint of comic books published by Marvel Comics, featuring reimagined and updated versions of the company's superhero characters, including Spider-Man, the X-Men, the Avengers, and the Fantastic Four. The imprint was launched in 2000 with the publication of the series...

 imprint. The Ultimate X-Men exist alongside other revamped Marvel characters in Ultimate Marvel titles including Ultimate Spider-Man

Ultimate Spider-Man

Ultimate Spider-Man was a superhero comic book series that was published by Marvel Comics from 2000 to 2009. The series is a modernized re-imagining of Marvel's long-running Spider-Man comic book franchise as part of its Ultimate Marvel imprint...

, Ultimate Fantastic Four

Ultimate Fantastic Four

Ultimate Fantastic Four is a superhero comic book series published by Marvel Comics. The series is a modernized re-imagining of Marvel's long-running Fantastic Four comic book franchise as part of its Ultimate Marvel imprint...

, and The Ultimates

Ultimates

The Ultimates is a fictional group of superheroes that appear in comic books published by Marvel Comics. The team was created by writer Mark Millar and artist Bryan Hitch, and first appeared in The Ultimates #1 , as part of the company's Ultimate Marvel imprint...

.

The protagonists are the X-Men, a group of mutants

Mutant (Marvel Comics)

In comic books published by Marvel Comics, a mutant is an organism who possesses a genetic trait called an X-gene that allows the mutant to naturally develop superhuman powers and abilities...

 whose unusual genetics grant them superpowers which set them apart from the rest of humanity.