This wasn't just Taker making a token appearance, there was real meaning behind this: besides the fact that Taker, at the time, was one of the longest tenured active superstars on the roster, he was paired up with Flair as an ally against Hulk Hogan way back in 1991 when Flair first entered WWE. Not to mention that at the time, Taker was the World Heavyweight Champion, holding the same Big Gold Belt that Flair himself had held so many times.
And during Wrestlemania 26, when Undertaker was going for his cutthroat taunt as Shawn Michaels was laid out on the mat, he suddenly stops, and just shrugs at the defiant Michaels struggling to get to his feet, clutching to him for support. He even yells at him to stay down, in a tone not too distant from begging. This is the Undertaker. Showing pity to his long-time opponent. At Wrestlemania. Only Shawn Michaels could invoke this Out-of-Character Moment from him.
Not to mention after the match, after doing his victory pose, he helps Michaels to his feet and shakes his hand before exiting to the back, letting Michaels have the spotlight one more time for the fans.
After WWE purchased WCW in 2001, thus giving them access to WCW's video library, WWE released the DVD Undertaker: This Is My Yard, which delved a lot into the real life Mark Callaway...sorry. At the end he is in the locker room talking to the other wrestlers during the InVasion/Alliance angle, he says these words.
"There's no shame in going out there and getting your ass kicked. There's no honor in not fighting at all."
Words to live by.
Wrestlemania XXVIII: Undertaker with the help of Shawn Michaels hoists Triple H on to his feet and carry him up the ramp and where they later hug. As the tagline for the match called it, it was the end of an era.
On Raw during March 11, 2013, following Paul Bearer's death, the Undertaker came out into the ring to personally pay tribute to his former manager the best way he knew how. The shot of him giving one final salute to the Paul Bearer's urn and the Jumbotron tribute of him is incredibly touching.
WrestleMania 30: After the punishing Streak-breaking loss to Brock Lesnar, Undertaker spent several minutes laying on the mat before painfully sitting up and slowly walking out of the arena - the entire time, the fans and commentators are applauding him; by comparison, Lesnar's victory had gotten nothing but shocked silence.
The night before, he arrives to pay tribute to Paul Bearer in the only way that he could - raising his signature urn in silence.
According to Kamala, Undertaker gave him a hug backstage at WrestleMania X-Seven.
More recently, the "Thank You Taker" chants, especially during the end of his matches in Hell in a Cell 2015 and Survivor Series 2015. A testament to how beloved he is.
'Taker winning the WWF title at WrestleMania 13, holding the strap high, and pointing to his fans in salute to his "Creatures of the Night."