Wolverine: Genetically blessed with accelerated healing, enhanced senses and bone claws, James "Logan" Howlett has fought in several wars and now possesses an adamantium-laced skeleton, making him the best there is at what he does. Once a loner, he recently founded a school to train young mutants.

Sabretooth: Victor Creed's origins are shrouded in mystery, he has Wolverine's mutant healing and tracking powers, but lacks morality and self-control. It is known that the two once worked together, and that Sabretooth killed Wolverine's lover, which has made things difficult when he has had to work alongside the X-Men.