The WWE career of The Undertaker is simply unparalleled. In a 30-year run with the company, "The Deadman" has faced off with nearly every major name in WWE history.In the final episode of #TheLastRide, the @undertaker sheds some light on what's next for 'The Deadman'. pic.twitter.com/hbg5OJchFA— WWE on FOX (@WWEonFOX) June 21, 2020Following his admission on the concluding episode of "Undertaker: The Last Ride" that he has likely wrestled his last match, tributes have poured in to celebrate The Undertaker's legendary career.From his debut at Survivor Series 1990 all the way to his Boneyard Match with AJ Styles at WrestleMania 36, The Undertaker's career has been packed with unforgettable moments and matches.Naturally, during that period, The Undertaker has also had a wide variety of intense rivalries. Which of these, though, have done the most to help solidify The Undertaker's legacy? With such a large body of work to choose from, it is hard to narrow down the 55-year-old's most memorable feuds.With that said, however, here is a countdown of The Undertaker's 5 greatest WWE rivalries.#5 "Stone Cold" Steve Austin vs The UndertakerJoin myself and the @undertaker on the Broken Skull Sessions. Right after @wwe #SurvivorSeries only on @WWENetwork. Sunday 11-24-19 pic.twitter.com/YbBY6vh90b— Steve Austin (@steveaustinBSR) November 20, 2019"Stone Cold" Steve Austin and The Undertaker were two of WWE's biggest stars during the Attitude Era, headlining multiple pay-per-view events together.The most high-profile of these was their main event clash at SummerSlam 1998, where Austin successfully retained his WWE Championship. The Undertaker would gain a measure of revenge, though, as he defeated Austin to win his third WWE title at Over The Edge the following year.The pair had many clashes other clashes throughout the years too, more often than not at the top of the card. WWE knew they could rely on The Undertaker and Austin to deliver every time, which is why the promotion revisited the combination frequently. The duo even had a brief run as WWE Tag Team Champions in the summer of 1998.Although they never squared off at WrestleMania, The Undertaker and Austin have a storied past, much of which unfolded during WWE's most successful period in history. This alone makes it hard to ignore Austin when talking about The Undertaker's biggest rivals.