Three days before WrestleMania 33 in 2017, The Undertaker made a decision. For the first time ever, he allowed Vince McMahon and WWE to follow him everywhere he went leading into his match with rising star Roman Reigns. The result was Undertaker: The Last Ride, a compelling five-part documentary series that kicks off Sunday after Money in the Bank on WWE Network.

For almost 30 years, WWE fans had gotten to know The Undertaker in his various forms—mythic Frankenstein's monster, redneck butt-kicker and evil cult leader. As he prepared for what everyone believed would be the last match of his career, we would finally meet Mark Calaway, a man so revered by his peers that every mention of his name was tinged with a sense of awe, respect given because it had been earned with a lifetime of blood and sweat.

Frankly, it was worth the wait. 

WWE shines in these moments, documenting its own lore, fetishizing the past and creating legends from what were once mere mortals. And all the trappings of the WWE documentary experience are here: the slow-motion highlight packages, the glimpse behind the curtain, the sufficiently significant interview subjects, the revealing car rides, the gruesome medical footage reminding us all not to try this at home.

Calaway has gravitas, a quiet confidence that doesn't require bravado. Others do his talking for him, extolling his virtues. Veteran performers stare in wonder as he enters a room, lining up to shake his hand. He's still the locker-room leader—we see him gently chastise Reigns as he comes up to check into the hotel while Taker is getting his own room key.

"You really can't kayfabe just 10 minutes?"

For the first time, Calaway reveals some of the professional secrets of being The Undertaker, the last of the cartoon gimmicks that populated 1980s wrestling who somehow became the realest guy in the room as the business transformed into the Attitude Era.

"Less is more," he says. "The pace of my matches was extremely slow. And then...bang. Something really fast would catch people off guard, like, 'I didn't know he could move like that.'"

We get a glimpse of his career as he battles superstars over the ages, toppling titans from Hulk Hogan to Brock Lesnar and everyone in between. But the focus is squarely on WrestleMania, pro wrestling's Super Bowl, and a stage where Calaway has truly shone. It's an event that brings tears to his eyes as he considers it on camera.

"The Streak is what made it OK for me to only work once a year," Undertaker said. "Because I had to defend The Streak. It takes its toll. I had a five-year stretch when my schedule would be, I would prepare for 'Mania, I would have my 'Mania match, I would have some kind of surgery to repair whatever had been bothering me going into that match and go right from rehab into training to go to 'Mania again."

His willingness to give his body, his wellbeing, his life to the industry didn't go unnoticed inside the company.

"What he was willing to sacrifice, what he was willing to do," WWE boss Vince McMahon said. "He gave everything he had."

But Last Ride transcends the excellent fare you've come to expect from WWE Network, veering from hagiography just enough to make me think I was watching something even better than pro wrestling myth-making—some version of the truth.

This documentary isn't for the faint of heart. There's sadness lurking throughout. The Deadman is facing his own mortality, with his first appearance on camera as himself a painfully compelling portrait of resignation, courage, despair and denial.

"People have no idea how much pain he's in physically," Undertaker's wife, former WWE wrestler Michelle McCool, said. "And how much pain he tolerates. And how many surgeries he's had. They don't understand."

While The Last Ride is ostensibly about his bout with Reigns, he started down that long road three years earlier in a match against Lesnar, which saw his legendary run of victories finally come to an end. It was also a match performed on autopilot, with an early slam outside the ring leaving him badly concussed. It's hard to watch the footage, showing the extent of his confusion, with his eyes looking forward but seeing nothing. 

McMahon ended that WrestleMania at the hospital, abandoning his company's biggest event to go with Lesnar to the hospital to be with his legendary warrior. Everyone was shaken as he couldn't remember his name, where he was or even what he'd been doing until late in the night.

It was a match that didn't just destroy The Streak—it very nearly destroyed the man as well.

"One concussion in one match destroyed my confidence," Undertaker reveals. "It was Triple H who really spotted it. I'm waiting to go out, just riddled with self-doubt and Triple H came to me like, 'Hey, remember who the f--k you are.' It was enough to get me through the match and restore my confidence."

The final third of the first episode focuses on the match with Reigns and everything it takes to get Calaway, a man who struggles just to limp around the stadium with his wife, ready for a big-time wrestling match.

"People say, 'All you've got to do is go out and chokeslam somebody, make your entrance,and everybody's going to be happy.' No. I'm not going to be happy," Undertaker said. "And this is not stupid man pride or cliche stuff. I'm either going to go out with a match that's befitting the Undertaker at WrestleMania or I'm going to out on my shield. One way or another."

Shots go into his knee and hip, but it's his confidence that needs the real pick-me-up. We watch him try to talk himself into this, with hindsight making it particularly tragic because the audience already knows what Calaway only suspects—it isn't going to end well.

The match was limited, not by a lack of creativity but by his own physical limitations. In what was to be his last ride, Undertaker wasn't thinking about how to best wow the crowd. He was worried about things like whether he would be able to get up if he went down to the mat too many times to sell Reigns' powerful offense.

In the end, he violated his own mantra: "Don't embarrass yourself. Don't embarrass the company. Don't embarrass Vince."

There's an awkwardness to the final moments here. Everyone backstage is clapping and congratulating Calaway while their sad eyes told another story, realizing he had overplayed his hand but not willing to admit it, even to themselves. Only McMahon, empowered by his position, could quietly admit the truth.

"He knew in his heart that it wasn't there," the WWE owner said.

Though Undertaker piled the regalia of his office in the middle of the ring, signaling his retirement, we know this wasn't the last match of his career. The remaining four episodes of the series will no doubt take us with him on the rest of his journey. And after this excellent opener, I can't wait to go on this ride.

Jonathan Snowden covers combat sports for Bleacher Report. Undertaker: The Last Ride, WWE's new five-episode limited series event will begin streaming on WWE Network on Sunday immediately following the Money In The Bank pay-per-view.