Undertaker began his wrestling career in 1984 before joining World Championship Wrestling as "Mean" Mark Callous five years later. In 1990, he started wrestling as The Undertaker with Paul Bearer as his mouthpiece (his original manager was Brother Love, but Paul Bearer replaced him within the first several weeks) in the World Wrestling Federation, making his debut at that year's Survivor Series. At the following year's event, Undertaker pinned WWF Champion Hulk Hogan to win his first World title. His reign was short-lived as Hogan regained the title the following week, but after losing the championship, Undertaker went from being a feared bad guy into one of the most loved fan favorites when he saved Randy Savage and Ms. Elizabeth from Jake The Snake Roberts.
For the next many years, Undertaker garnered a reputation within the WWF as a monster slayer, taking on the likes of Yokozuna, Mankind, Diesel, Vader, Giant Gonzales, Kamala, and even an impostor Undertaker, before he finally won his second World title at WrestleMania the 13th by dethroning Psycho Sid. During his reign, Paul Bearer announced that Taker had a long-lost half-brother named Kane who had been presumed dead for years. The two began a tumultuous relationship as enemies and partners over the next several years. In early 1999, Undertaker started a darker, more dangerous persona, even founding the Ministry of Darkness, through which he was able to win his third World title.
Despite forging a gimmick as the Deadman, Undertaker assumed an "American Badass" persona from 2000-2003, although he retained the same character throughout this period. Taker was a fan favorite, facing a variety of opponents, often teaming with Kane as the Brothers of Destruction. In November 2001, Taker turned on the fans and began demanding their respect. During this time, he defeated Hulk Hogan for his fourth World title in May 2002. He regained fan support in September 2002 when he challenged the new WWE Champion Brock Lesnar. After Vince McMahon cost Taker a title match with Brock in October 2003, the two had a brief feud which culminated in a Buried Alive match at Survivor Series, which Vince won with help from Kane.
Undertaker made his long-awaited return at WrestleMania XX, where he defeated Kane in a grudge match. Since that time, Undertaker has been all business, winning three more World titles at the expense of Batista, Edge, and (most recently) CM Punk, but even when he isn't holding a championship, he remains one of the most marked men in WWE today.