Triple H and The Undertaker are the ones putting together their current program for WrestleMania 27, with minimal input from WWE creative.
Taker was originally scheduled to face Wade Barrett and Triple H was set to face Sheamus at WrestleMania but the two got together and realized that WrestleMania 27 had no special match. As WWE’s two most power political forces, they felt they could take control of their own angle without much in the way of outside influence.
Shawn Michaels is still expected to be introduced into the storyline and have a role at WrestleMania, possibly as a referee or an enforcer. The idea behind the storyline is that Triple H is going at Taker for revenge after Taker ended his best friend’s career.
Source: Wrestling Observer Newsletter