Shawn Michael's is undertakers next opponent at WrestleMania 26.
The Undertakers first Wrestlemania was Wrestlemania 7, which was where he succesfully beat Jimmy Snuka
The undertakers next match is at wrestlemania 28 where he is going to face hhh
Hopefully! However as the match between Triple H and The Undertaker at WrestleMania 28 was named the 'End of An Era' match I pressume this is the Undertakers last match and hence, the end of the Undertakers era. But, you never know, The Undertaker is a strong guy for 47, so you never know, but I think I'm right in thinking this is the end of the Undertakers streak at WrestleMania :'(
Batista
NO
The Undertaker defeated Triple H at WrestleMania 27.
Randy Orton
edge
He currently has an 18-0 streak on WrestleMania.
grave of his wrestlemania opponents whom he defeated one by one
No one knows yet. That hasn't been revealed.