Who he is: Sabretooth, a.k.a. Victor Creed
His power: Sabretooth can heal from most physical injuries and is immune to disease and the decay of old age, making him effectively immortal. He also has razor-sharp claws, enhanced senses, and superhuman strength, speed, and agility.
His story: Sabretooth is Wolverine’s evil half brother, and after they ran away from home in 1845, they stuck together and fought in the American Civil War, both World Wars, and the Vietnam War. X-Men Origins: Wolverine details Victor and Logan’s troubled past, and the half brothers part ways after serving on William Stryker’s Team X in 1973. Sabretooth remains in Stryker’s employ while Logan makes a new life for himself, but their paths cross again when Victor starts killing old members of the team and takes out Logan’s new girlfriend. Despite their differences, the two end up working together once more to take out Stryker’s Weapon XI mutant hybrid. Sabretooth disappears for decades after the fight, showing up again in X-Men as one of the members of Magneto’s Brotherhood. This especially shaggy Sabretooth is last seen getting shot off the Statue Of Liberty by Cyclops’ optic blast, but it takes far more than that to kill him.
Played by: Michael-James Olsen (young) and Liev Schreiber (adult) in X-Men Origins: Wolverine; Tyler Mane in X-Men.
Currently, Sabretooth is: The timeline changes of X-Men: Days Of Future Past make Sabretooth’s current status unknown, but he’s out there somewhere, thinking up ways to fuck with his little brother.
Where will we see him next? Sabretooth didn’t show up for Logan, so your guess is as good as ours.