Over the past six or so years, the WWE Universe waited in suspense about The Undertaker's inevitable retirement announcement.

On the fifth and final episode of Undertaker: The Last Ride, the Deadman announced his retirement from professional wrestling. He cited the need to spend more time with family as well as having "no desire to get back in the ring" as reasons for his retirement.

And so ends a historic, legendary and near-flawless 30-year run for the greatest superstar in WWE history. Yes, I said it.

Plenty of all time greats have suited up for Vince McMahon's wrestling promotion, winning over the hearts and minds of millions of fans across the world. But The Undertaker was truly a once in a generation talent who will not be replaced.

After a brief stint with WCW, Undertaker signed with the WWE in 1990 at the young age of 25. His horror-themed and dark gimmick quickly got The Undertaker over, and it didn't take Vince long to realize he had a future main event superstar on his hands.

Over his 30-year run as a wrestler for WWE, Undertaker embodied every major category you need in a superstar. For starters, there is no gimmick and character more compelling than that of The Undertaker.

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He kept it fresh and exciting time and time again. No superstar succeeded in reinventing themselves as much as The Undertaker. He was never boring. Fans never got tired/bored of him the way they did with other major superstars such as Hulk Hogan and John Cena.

It wasn't just his character, either. The Undertaker will be the first to tell you that he wasn't on the level of Shawn Michaels when it came to in-ring performances, but his work as an actual wrestler was nothing short of spectacular. There are countless wrestling icons who were incredibly lackluster in the ring (they know who they are).

But Undertaker isn't only the best WWE superstar ever because of his work as a character/wrestler. He was also the ultimate locker room leader for the better part of two decades, especially in the '90s when there was nonstop backstage drama between other superstars.

It's no surprise that Vince McMahon mentioned The Undertaker as his favorite wrestler during an interview with Muscle & Fitness. The WWE chairman had falling outs with other major stars such as Hogan, Ultimate Warrior, Randy Savage, and Bret Hart.

But his relationship with The Undertaker was similar to that of a father and a son. Vince knew he could rely on Mark Calaway to keep things afloat in the locker room. At the same time, Undertaker wasn't afraid to confront Vince for doing the wrong thing (such as the Montreal Screwjob incident).

There are also plenty of timeless stories about The Undertaker running "Wrestler's Court", where he would hear backstage problems between wrestlers before coming up with a solution.

If WWE didn't have a leader like that during the Monday Night Wars with WCW, who knows how bad things could have gotten there? Maybe Ted Turner's company would have put Vince out of business instead.

The Undertaker even admitted that there was interest in signing with WCW, but he ultimately chose to stay loyal to the man who gave him the opportunity to become a legend.

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While many other big-named WWE superstars left for more money in WCW, The Undertaker was intent on sticking around to build the best product possible with Vince. He ended up making the right decision, to say the least.

There are plenty of stories about major wrestling icons refusing to help and/or put over younger talents (again, they know who they are). Undertaker was the opposite. He often took them under his wing and tried to help them become the best wrestler possible. This was seen on The Last Ride with Cena and Randy Orton, and he's been doing it aplenty with today's NXT superstars.

Even in the later stages of his career, Undertaker was perfectly fine surrendering his perfect WrestleMania streak to Brock Lesnar, and he happily tried putting Roman Reigns over at WrestleMania 33.

Where would WrestleMania be today without The Undertaker's streak? Even though he won 25 of 27 matches on the Grandest Stage of Them All, just think about how much those matches helped enhance the pushes and legacies of other superstars - including Ric Flair, Kane, Orton, Edge and Michaels.

Indeed, The Undertaker was as complete as they come in a WWE superstar.

He had the longevity, loyalty, in-ring talent, character/gimmick, leadership, selflessness and countless career accomplishments to cement his case as the greatest WWE superstar of all time.

In the final episode of The Last Ride, The Undertaker didn't fully rule out retirement. He said he would think about it if Vince reached out to him again. So maybe we haven't seen the last of him in the ring.

But if we have, well, we just wanted to say "Farewell" and "Thank you" to the greatest superstar in WWE history.

NEXT: Wrestlers React To The Undertaker's Retirement Announcement