Last December, NetherRealm Studios unveiled their latest free-to-play app: WWE Immortals! The partnership between NRS, Phosphor Games, and the wrestling giant meant an interesting meshing of style and subject matter!

With Johnny Cage jumping into the ring as a guest fighter in Immortals, we've been thinking about how Cage might come to blows with WWE - but what about the other way around?

World Wrestling Entertainment has been a powerhouse in its current incarnation since the mid-eighties. Its lineage goes even further back, tapping into the traditions and culture of a century of professional wrestling! Today, WWE runs at least 6 hours of original content every week, on an unending cycle year after year. There's a lot to learn from that, and we've narrowed it down to five key things the makers of Mortal Kombat could consider after their brush with WWE!

1. Book Stars Strong, Get Talent Over
Historically speaking; Mortal Kombat has outpaced the fighting game competition when it comes to giving their characters backstory, and active goals to pursue. It's one of the qualities we love most about Mortal Kombat, but they aren't always so reliable when it comes to giving main event threats their due.

Weak booking -- wrestling jargon for the layout of characters, match-ups, results, and key interactions -- has hurt the reception and credibility of many a kombatant.

Over the course of its twenty-year history, the series has been particularly notorious for undercutting its kingpin characters, relying on spoken lore to establish the credibility of their icons. Until recently, screen time and dialogue often meant embarrassment for heroes who were booked to look like idiots, and villains who were coasting on rumors, and simply waiting to get their butts kicked.

It's an inherent risk for the villains - who typically do exist to be beaten up, especially in fighting games - but that's where good booking comes in!

Shinnok received a second chance in Mortal Kombat X thanks to a reboot timeline do-over of Mortal Kombat 4. No boss in series history had been more disrespected than Shinnok, who we were told led a slaughter against the gods, but arrived in-game as a thoroughly unremarkable, selectable character in '97. MKX tackled that problem with a better design, unique moves, and a suped up Corrupt boss version that created distance between the big bad and the rest of the roster. Unfortunately, story mode still booked him weak - making his two biggest moments defeat at the hands of comedy relief Johnny Cage, and later, junior newcomer Cassie Cage!

Because neither protagonist had been booked to have the gravitas to go toe-to-toe with a god - Shinnok looked incredibly weak once again. Not as weak as he did in MK4, but a cut below the villain who we're told successfully conquered Earthrealm, but were only shown getting beat up by a goofball and his plucky sidekick! Pre-ordained 'special genetics'? Magic ticket my ass, McBain!

Other characters suffered from bad booking in MKX, most notoriously Goro - who was otherwise elevated in status with a pre-order campaign that created a real sense of occasion around his return! Being playable was to be a boon to his stature - which had diminished over previous years of being knocked around as an all-too beatable villain who wasn't even treated like an MK Champion in the last game! Unfortunately, the return promos and special preview event didn't go much further.His total absence from Story Mode led many fans to write him off as inconsequential.

It was a real missed opportunity for one of the series' original icons! A fumbling the scale of Taz, who entered WWF to one of the loudest receptions in memory - only to tumble into Hardcore title obscurity, shortly thereafter!

2. Create New Stars
In terms of creating new icons from scratch, Mortal Kombat X did the best job we've seen since the original trilogy! Like The Radicalz joining WWF in 2000; MKX's new fighters introduced an influx of technical ability, new gimmicks, and new match-ups. So fresh was gun slinging mercenary Erron Black, he shot instantly to the top of many fans' lists of favourite characters! Kotal Kahn represents another unique addition we see no reason to discard any time in the near future. These are characters the next game could very well build around - no mean feat!

Professional wrestling rarely has the luxury of inventing new icons from thin air. Many of the very best WWE wrestlers have come from the now defunct territory system, or other independent modes of preparation, providing a base of understanding to utilize a wrestler's strengths and skills. Like our first point, it's all about hiding the weaknesses, and emphasizing the strengths.

Recent golden child Roman Reigns reminds us that there's no guarantee when it comes to manufacturing new stars, but sensitivity for the mood of the crowd, and careful enhancement of talent is a major part of successful sports entertainment. Before "Stone Cold" Steve Austin and The Rock were two of the biggest icons in wrestling, they were mid-tier wrestlers looking for a way to get ahead of dubious gimmicks. Austin shook off his past as a Hollywood Blonde and generic Ring Master to become a trash talking S.O.B. Rocky Maivia left behind the tassels and hand-picked babyface grin to unleash the arrogant charisma of The Most Electrifying Man In Sports Entertainment!

Ermac represents an existing Mortal Kombat character who had the world at his feet. Beginning life in Ultimate Mortal Kombat 3 as an April Fool turned red palette swap, he grew into a massive cult favourite. Booked remarkably strong in Mortal Kombat (2011), he could have been equal to Scorpion and Sub-Zero, were it not for some severe missteps in Mortal Kombat X. Rather than enhancing the intrigue of the faceless legion character, new designs exposed his face without explanation and further stripped him of iconic red, while Story Mode sacrificed his power for a role as a minion.

On the flipside, elevating Johnny Cage as one of the games big heroes, and crossing him over with WWE Immortals [promoted by a character-driven trailer], has gone a long way to boosting his cache! At a time when fans are rejecting the John Cena-like omnipresence of company mascot Scorpion, this is the right way to go.

3. Equity in Personal Issues & Rivalries
Booking and sensing potential upgrades are the tools for building any empire, but for lasting longevity in a combat environment, characters need more than positioning - they need a nemesis!

Perceivable, genuine animosity built Bret Hart & Shawn Michaels into one of wrestling's hottest feuds! The boiling point of the "Montreal Screwjob" -- still one of wrestling's most talked about moments -- was merely the conclusion to what had already been a bitter, drag-out feud in the years prior! Triple H lagged in his initial push toward World Championship status in 1999, but his nemesis Cactus Jack (aka; Mick Foley) truly cemented his reign a year later, capitalizing on a feud that went back to 1997 with a higher level of spectacle and competition! Sting had Ric Flair, The Rock had Stone Cold, Kane had The Undertaker, Seth Rollins has John Cena!

Rivalries and counterparts have been a fundamental aspect of most successful fighting games - Mortal Kombat included! Director Paul Anderson recounted fandoms' reaction to Scorpion & Sub-Zero as allies during his work with the MK movie. Rivalries give greater meaning to a fight and help define the principles and motivation of combat characters. The heroes of the original trilogy have loomed large thanks to their rivalries, but it's something lacking from recent installments.

The world of WWE offers an extensive catalogue of classic feuds, varied in their vitriol and style. Some are sports-like in their competitive, skill based nature. Others boil up from the gut, based on an innate hatred, or personal grievance. In its peak "Attitude Era" of the nineties, WWF boasted clearly defined characters who all found enemies to bounce off of. This presentation of vivid archetypes was the perfect model for a fighting game, where time isn't always spread evenly, and characters need quick hooks to give their presence meaning.

Mortal Kombat X flirted with a few rivalries, but we want to see characters who enter the arena with a grudge to bear. Every Street Fighter has an in-built opponent, and Mortal Kombat should be no different. When Quan Chi was introduced to the series, he was revealed to be responsible for Scorpion's curse, elevating himself above minion level, and enhancing existing characters. Sonya had Kano, Liu Kang had Shang Tsung, Raiden had Shao Kahn, and the Mortal Kombat X comics showed us many forgotten characters can mean more with new rivalries.

4. Long Term Booking Works
WWE doesn't have an off season. They perform and tour all year, structuring their schedule around key annual events, like Wrestlemania at the end of Q1,and Summerslam in August. Having tent pole occasions like Wrestlemania, as well as the monthly pay-per-view and network specials, gives their hectic weekly schedule objective points to build toward. That may not mirror the release pattern of Mortal Kombat video games, but it's parallel in its juggling of spontaneity and planned destination points.

At their best, WWE have usually begun formulating their Wrestlemania pinnacle by December and January, manoeuvring the pieces around a few key, marquee storylines and matches. Due to the rigors of their schedule, they can exercise caution where the important players are concerned, and keep their options open lower on the card.

At Mortal Kombat's best, they too have had future plotlines steering events, with an element of spontaneity coming from the mid-tier. The original game proposed the dangers of Shao Kahn and Outworld, but for the best example we look at Deadly Alliance! Here, all creative cylinders were firing, not only creating a vibrant reinvention of the series at that time, but storing up the next chapter with foreboding allusions to The Dragon King!

For twenty years, Mortal Kombat has produced sequels without fail. At this point, it's very difficult to excuse a lack of foresight. The revolving door of death in Mortal Kombat may be the softest target for a lack of foresight. All too often the series canon has written cheques it can't cash -- especially with the 2011 reboot, which slaughtered its icons. This raised the ire of fans when the heroes inevitably returned in the next instalment with "living" designs that defied their revenant logic.

Mortal Kombat (2011) did forecast the sequel we eventually got, which arguably gave fans a focal point to build toward one of the series' biggest launches ever! Mortal Kombat X also left fans with a similar teaser, Revenant Liu Kang & Kitana together as a darkened Raiden looked ambiguously to the future. Cliff hangers are the easy part, but the wisdom of long term booking is in the pedestrian details of Story Mode and the fates of individual characters.

5. Maximize The Lineage
In terms of market, Mortal Kombat has done wonders under Warner Brothers when selling its history! The Arcade Klassics are available to buy and play, and their beloved icons are immortalized in premium merchandise! Even the last installment of the series enjoyed a boost in sales with the announcement of Mortal Kombat X in 2014! The fiction that connects the past with the present hasn't fared quite so well, though.

When the patches and DLC stop, and controllers are put down for the final time, it's usually the characters and story that keep the series alive! Sadly, the franchise shed some its complexities with the reboot in 2011, which lopped off a majority of the 20 year canon to create a new retelling of the original trilogy. The result had its good and bad. At times, MK2011 created connective tissue and embellished the presence of obscure characters. At other times, it awkwardly truncated landmark moments, retconned clumsy alternative history, and altered the timeline in ways dramatically and inevitably undone by 2015.

WWE has had its own issues with managing history, but still does a brilliant job of capitalizing on its legendary stars, and deep back catalogue. The WWE Network allows neophyte fans to get an education in canon much the same way fan forums and paedias do for MK. The WWE Championships, too, provide a direct, unbroken line between burgeoning talent of today, and immortals of yesterday. Wrestlemania - the showcase for these immortals of tomorrow, today, and yesterday.

What's done is done, but we hope Mortal Kombat can learn to love its complicated history, and channel it in ways that never make it a burden! If all these lessons are learned from WWE, then Mortal Kombat can live forever, flourishing whilst setting the trends that all rivals aspire to! If there's no past, there's no future. Lets move forward, but never lose what's behind us!

[Related Article: Kountdown: Top 10 WWE Immortals Feuds for Johnny Cage]

The Johnny Cage Challenge is available now in Immortals! Will you learn lessons from WWE? Register to discuss the surprise X-over in the Mortal Kombat X forum! Share what you know by liking & sharing stories via @MK_Online, Facebook & YouTube!