A man with the same healing and the same claws as Logan, and none of the reasons to stop.
Sabretooth is Logan with the brakes removed, which is the only thing he needs to be. Tyler Mane plays him in the first film as a physical problem: bigger, faster, and clearly enjoying it. Liev Schreiber plays a different reading entirely in Origins, where he is written as Logan’s brother and given most of the film’s actual grief.
Two performances, two ideas, and no attempt to reconcile them, which is a fair description of the Fox run as a whole.