The Shiver Man is an enigma. Many rumors surround his origins, from being a soul condemned to walk the earth forever for some unknown crime to killing Jimmy Hoffa. What is known is this - He is an undead bounty hunter. He has worked with Nick Fury in the past, when Fury has had to go outside of S.H.I.E.L.D. to accomplish his goals. One such time was when Wolverine was a fugitive, hunted for supposedly murdering a high-ranking senator.
Fury hired the Shiver Man to bring the fugitive Wolverine directly to him instead of S.H.I.E.L.D. The Shiver Man tracked Wolverine and Beast to a parking lot outside a small rural town, and comensed to attack them, sensing that Wolverine was guilty of the murder.
Retreating after losing his left arm, the Shiver Man begins to rethink his strategy, only to lose his quarry to a corrupt faction of S.H.I.E.L.D. led by Agent Brent Jackson. Fury later summoned Shiv to trail Jackson and dig up some dirt on him; but Fury would have never guessed just how dirty Jackson was.
Jackson had Wolverine broken out of the Cage by Sabretooth, currently a member of the Weapon X Program, and brought with an injured Beast to the new Weapon X facility. There, the Shiver Man staged a daring rescue, destroying the facility, killing inumerable grunts (with the help of Wolverine), destroying the Program's files on all past Weapon X empolyees and test subjects, and entering into a pitched battle to the death with Sabretooth (which was kind of pointless, since each could recover from nearly any wound imaginable), which Shiv won.
However, feeling that, because the Weapon X Program had been controlling Wolverine's mind during the murder, his guilt should be alleviated, yet still haunted by his curse to avenge innocent blood, the Shiver Man dissipated before he could confront Wolverine again.