WWE's weekly Smackdown broadcast is now fifteen years old. The Undertaker is without doubt the most important wrestler to have competed on the show in those fifteen years, increasing both his and the blue brand's reputation in the process. You might call him 'Mr Smackdown', such was the hand in hand association. What is all the more remarkable about Undertaker's Smackdown legacy is that it came after so much previous success. Before the 1999 debut of Smackdown, he was already an established WWF veteran. He had became globally famous in his original early 90's Deadman role, going on to even greater fame when he became the edgier Undertaker of 1997 and 1998. There were so many great angles and matches in those 90's glory days, so much so that he was already well established as a Raw staple. Then came Smackdown in 1999. It would prove to be a recurring haunt for Undertaker, with many major angles taking place on the Thursday night show. However, it wasn't until 2002 that Undertaker really came to represent the Smackdown brand. The 'brand extension' meant that he was now an exclusive star of the blue broadcast, something which WWE and Mark Calaway really ran with. The Undertaker became the most important character in Smackdown history, creating a legacy and an era that made him Mr Smackdown. His work on the blue brand would go on to far surpass his earlier 90's work. Here's the ten reasons why he defined WWE's fifteen year show.