WWE Royal Rumble 2016: Biggest X-Factors to Watch at Massive PPV

The Royal Rumble is deservedly one of the highlights on any WWE fan's calendar.

The event has long been established as the start of The Road to WrestleMania. By the end of the show, we should have a good idea of what the card for The Showcase of the Immortals will look like.

However, this year in particular it's difficult to guess at what WWE has planned for the impending spectacle of WrestleMania. It seems all but certain that Roman Reigns will be entering the event as champion, but there's little else that we can say with any degree of certainty.

That will all have changed by the end of the 2016 Royal Rumble. WWE will at least have teased all the major matches set for the show, if not setting them up explicitly. For many fans, that makes the Royal Rumble a must-watch PPV year in and year out.

Here's a primer on the biggest X-factors to watch during the Jan. 24 pay-per-view.

John Cena Makes His Return

Credit: WWE.com

John Cena arguably had the best in-ring year of his career in 2015—until a loss against Alberto Del Rio at Hell in a Cell robbed him of the United States Championship.

Cena is scheduled to make his return imminently, and a rematch with Del Rio will likely be among his first orders of business. However, there's also a decent chance that he's gearing up to focus on the Royal Rumble itself.

The WWE workhorse is as strong a candidate as any other to challenge Roman Reigns for his world title in the main event of WrestleMania. In fact, he's uniquely poised as a big-name contender who could turn the bout into a bona fide headliner.

Pitting Cena against Reigns presents the match as a passing of the torch. If the company is keen to kick-start Reigns' time at the top, there's little better way than having him knock off Cena on The Grandest Stage of Them All.

Cena might have other plans come WrestleMania—a match against the Undertaker would seem to be another potent possibility—but a strong showing in the Rumble seems very likely.

The Wyatt Family Takes Everything

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The Wyatt Family has spent much of 2015 recuperating, but that preparation might pay dividends as we head into the new year.

Bray might not have picked up as many big victories as he perhaps should have over the course of this year, but he's in a power position with his family behind him.

Now it's a question of what The New Face of Fear can do with the resources available to him. It seems too soon for Wyatt to chase the world title, given that he was mired in a lengthy feud with Roman Reigns just a few months ago—but a recent tweet suggests he has big plans.

Last year, we saw The Authority use numbers to dominate the Royal Rumble, and it seems like we might see a different faction run a similar strategy this time around.

Unexpected Returns and Debuts

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One of the most exciting parts of the Royal Rumble is seeing who enters the 30-man match as a complete surprise.

We're likely to see one or two faces from yesteryear—and there's even the possibility of some NXT call-ups. This year's show saw Bubba Ray Dudley enter the bout; of course, he returned more officially with brother D-Von later in the year.

Given that the idea behind these appearances is to surprise fans, it's difficult to put forward a guess at exactly who will make the cut.

However, the list of possible NXT graduates is a little easier to predict. Sami Zayn seems poised to make the jump—and a feud with Kevin Owens in WrestleMania season would certainly be one way of jump-starting his following.

It wouldn't be surprising to see Baron Corbin, another NXT standout, debut during the Rumble. A Battle Royal is the perfect setting for a such an imposing competitor to make an impression, and Corbin seems likely to have a very successful 2016.

The Beast Comes Back?

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Having started out the year as a dominant champion, Brock Lesnar spent the latter part of 2015 embroiled in a blood feud with The Undertaker.

Now, it seems like his issue with The Deadman has been resolved once and for all. For Lesnar, that surely means that the next priority will be regaining the world title.

If Lesnar enters the Royal Rumble, he has to become the favourite to win, whatever number he ends up drawing. There is simply no one on the roster who seems capable of taking down the man who's run roughshod over the company for the past few years.

It isn't so much a case of whether Lesnar can win the Rumble as much as whether Roman Reigns can hope to make a successful defence at WrestleMania if challenged by The Beast Incarnate.

Conventional wisdom would suggest that no one can stop Lesnar—but that might be just the opportunity Reigns needs to solidify his position at the top of the ladder.