The Undertaker (real name Mark Callaway) is a professional wrestler. He got his first big break in WCW (then known as "Mean" Mark Callous) as part of a tag team known as "The Skyscrapers", but otherwise did nothing of note there.

He joined the World Wrestling Federation in 1990 and has worked for them ever since--thus making him one of the company's most loyal and reliable performers. He was introduced as Ted DiBiase's mystery partner at Survivor Series '90, with Brother Love as his manager, but Brother Love was soon dropped in favor of Paul Bearer (as typical of the WWF at the time, character names were as corny as humanly possible).

As heel (bad guy), his initial reign of terror stands unparalleled even today--fan reaction to him was so strong, in fact, that the WWF decided to job Hulk Hogan to him...cleanly...giving him the WWF Championship at Survivor Series '91--only a scant year after he joined the federation.

There has only ever been one Undertaker, despite rumors that Callaway had been replaced by another wrestler. Much of the confusion came about in 1994, when Ted DiBiase introduced a fake Undertaker (actually Brian Lee). Callaway (who had been taking time off for family matters) soon returned and kicked the snot out of the "Underfaker/Overtaker/Fake Undertaker" (the name Lee's character became jokingly known as). This was all part of the storyline; Callaway was never meant to be replaced by Lee.

A second source of confusion arose in 1995, when Undertaker started wearing a mask as a result, supposedly, of vicious legdrops given to him by Mabel. Many thought that his facial features appeared different while he was under the mask--and Callaway may (or may not) have had plastic surgery during that period--but it was always Callaway.

In an attempt to revive his stale character, Undertaker became the leader of the Ministry of Darkness in 1998--this was a satanic cult of sorts that went around kidnapping people and writing weird symbols on them. It was about as hokey as it sounded.

'Taker abandoned the whole "dead man" character entirely in 2000 after returning from a nagging injury that had kept him on the sidelines for the better part of a year. He was still known as the Undertaker, but now was more of an American Badass--he wore a bandana, rode a motorcycle down to the ring, chewed tobacco, and so on. The idea worked, and he received more heat than he had in years.

Callaway has stated that he only wants to wrestle for another year or two before retiring (as of 2000)...whether he stays true to that statement remains to be seen.

While Undertaker's ability as a technical wrestler is spotty at best, by all reports he is a true gentleman and a leader in the locker room--and above all loyal to his company, a fact evidenced by the fact that he's worked continuously for the WWF for a nearly a decade, longer by far than any other wrestler on the roster.