For almost as long as Wolverine has been a superhero, his enemy has been Sabretooth. Originally the two served together under both the Team-X and Weapon-X programs.

Originally the pair meets in Team X, with team members Kestrel and Maverick. Sabretooth embraces his violent side at all times, and on one mission, kills a crucial scientist during a battle against Russian supersoldier Omega Red. He frequently targets and kills civilians during other fights involving the loose-knit team, but he remains loose friends with Logan. 

Later, they are both recruited into the Weapon-X program where Wolverine receives his Adamantium upgrade. It remains unclear if Sabretooth receives any enhancements to his mutant structure. During this time they begin to find each other on opposite sides of the table, where Sabretooth's violent nature often gets the best of him. Eventually, Sabretooth kills Silver Fox, Wolverine's lover who also joined the Weapon X program. While this memory is slowly erased from Wolverine's mind by his healing ability, his disdain for Sabretooth remains even if he can never rememeber the source of his hatred.

Sabretooth's Powers

Superhuman Strength, Stamina, Endurance and Agility: These powers allow Sabretooth to move faster, fight without fatigue, hit harder and live longer.

Superhuman Reflexes and Ligamentation: Sabretooth's ability to spring, leap and tumble far exceed that of any other known living mutant. The tension in his ligaments and ability to instantaneously relax and reflex his muscles permit him to bolt forward faster than an eye blink, often confounding attempts to counter him. Only a few superheros are capable of reacting to Sabretooth's pounce before being hit by it.

Reggenerative Healing Factor (a requirement for membership into the original Weapon X program) - an ability to not only mend damaged tissue, but also to regrow or reattached severed limbs.

Heightened senses of smell, scent tracking, danger awareness and animalistic instincts. Sabretooth also posseses full nocturnal vision. It is conjectured by some that Sabretooth has an sense for lunar alignment, which drives him on Wolverine's birthday to scent-track and attack the X member, often in the middle of the night.