Undetermined. Gathered for Steve Rogers' ad hoc team of Avengers comprised of inverted villains in Avengers & X-Men: Axis #6. Later pressganged by Rogue to work with the Unity Division in Uncanny Avengers (2nd series) #1. Jarvis indicated the official records were uncertain about Creed's status in Deadpool (5th series) #8.
Sabretooth had his physical powers increased by Graydon Creed years ago in Sabretooth (1st series) #1. He first received an adamantium skeleton just prior to Wolverine's marriage to Viper in Wolverine (2nd series) #126. It was later removed from his body by Apocalypse to transform Logan into the adamantium-enhanced Death in Wolverine (2nd series) #145. Creed suffered from adamantium withdrawl (as opposed to adamantium poisoning) until Gambit acquired the Constrictor's coils for him. Creed somehow lost this adamantium as well, and was given a new set of adamantium implants and strength enhancement by the new Weapon X Program.
Sabretooth's true name was revealed in X-Men (2nd series) #5 and Sabretooth (1st series) #1.
Sabretooth was decapitated by Wolverine using the Muramasa blade in Wolverine (3rd series) #55. He resurfaced alive and well in Wolverine (4th series) #20. The details of his return were shown in "Sabretooth Reborn" from Wolverine (2nd series) #310-313, where it was established he used a clone as a stand-in when Wolverine apparently killed him.