Paul Bearer (real name William Moody) (1954-2013) was a WWE manager and former wrestler, best known for his years managing The Undertaker. During the course of his tenure at WWE, he also managed Mankind, Vader and Kane. In kayfabe, his character was portrayed as a funeral director with certain mystical powers centered around an urn that he carried with him that seemed to empower whoever he managed. He was also later revealed to be the biological father of Undertaker's half-brother Kane.He had also been a funeral director and mortician in Real Life, which was the inspiration for the gimmick.He passed away due to complications from a blood clot on March 5, 2013. This didn't stop the WWE from using his (supposed) ashes as a gimmick in various matches. The next year, Paul Bearer would be inducted into the WWE Hall of Fame.The Other Wiki has a more detailed rundown of his career and kayfabe history here.
"You can read my tropes, Ooooh YEEESSS!":
Acrofatic: He actually took some impressive bumps every now and then, and could dart away pretty quick when it looked like he was going to be attacked at ringside.
Action Survivor: Had been a wrestler under the names the Embalmer, the Mortician and Dr. X before settling into his role as a manager.
I Am His Father: Revealed that he was Kane's father the day after Unforgiven when Kane's arm was engulfed in flames after the first Inferno match. Later related the entire story in an interview segment with Jerry Lawler.
I Have Many Names: The Embalmer, the Mortician, Mr. X, Percival "Percy" Pringle III, Paul Bearer.
The Load: The reason Undertaker gave for burying him in cement in 2004. He's also proven to be this to Kane after his 2010 return, which is partly why he didn't rush to save him in 2012 when Orton kidnapped him.
Talk Show with Fists: "The Funeral Parlor", an interview segment he had with The Undertaker in the early 1990s. His show replaced "The Brother Love Show," which was where he debuted shortly before WrestleMania VII, replacing Brother Love as Taker's manager.