The X-Men learn that the man they thought was Wolverine is actually a Skrull. But if that is true, then where is the real Logan?
Wolverine gets kiddnapped by Apocalypse, and forced to battle Sabretooth. Who ever wins the battle becomes the new Horseman of War. Since Wolverine thinks he can get free from Apocalypse's mind control, he defeats Sabretooth, than becomes the Horseman of War and gets Sabretooth's adamantium skeleton and he battles the Hulk.
After the X-Men learn that the man they thought was Wolveerine was nothing more than a skrull imposter, it is learned how it occured. After their mission to a training ground for the skrulls in space, Wolverine was abducted by the skrulls and taken to their master. There he pitted Sabretooth, and Wolverine against each other for the right to become the new horsemen of death. Even though Wolverine is facing a larger, stronger opponet with his bone claws versus an adamantium skeleton, Wolverine determines that Sabretooth would be a merciless killer while he could beat the programming. After winning, he is again infused with the adamantium taken from Sabretooth. In the present, Death (in truth Wolverine), takes on the Incredible Hulk. It is a monumental battle, and near the end, he has a chance to kill the green monster. However, he hesitates, and the Hulk is able to punch his foe and rushes off. Once the Hulk departs, Apocalypse teleports Death up to his location and informs him of his new era - the age of Apocalypse!