Bungie has had a few stellar hits in their day. After the success of Marathon, their sci-fi first-person shooter Halo: Combat Evolved shattered records, launched the first Xbox console into the stratosphere and sold more than 6 million copies when it dropped in 2001.

Bungie had at least a small hand in two more main-series titles, as well as three additional spin-off games. Halo 2 and Halo 3 sold more than 20 million copies together, while real-time strategy entry Halo Wars brought the sci-fi series to a new fanbase.

Finally, the developers wrapped their involvement with the series as they moved away from the story of the Master Chief and detailed first an infantryman in ODST. Then they added an immersive prequel story that took us to one of the biggest moments in the Halo universe - the Fall of Reach.

Halo has continued without Bungie, but the inventive developing team moved on to new things after the release of Halo Reach in 2010. That was, of course, the online-only multiplayer first-person shooter we've come to know and love, Destiny.

Where Halo broke barriers in the early 00s with how FPS titles were seen, Destiny changed the face of looter-shooters for a new generation. Now, curious Guardians are beginning to believe there's a link between the two gargantuan Bungie franchises.

The theory mainly stems from a quote the Master Chief's AI companion Cortana says in the first playable mission of Halo 2, Cairo Station. During the beginning of the mission, Cortana tells the players she's heard "Whispers" coming from Io, Jupiter's moon.

"Another whisper sir, near Io. We have probes en route," Cortana tells Fleet Admiral Lord Terrence Hood during the game's opening medal ceremony for the Master Chief and Sergeant Major Johnson.

Now Halo fans are sure to jump to attention at this. The whispers she hears are likely the Covenant on their way to Earth. The mission, after all, then becomes a space-based battle against the coalition of enemy races as they accidentally discover the location of humanity's homeworld.

But that's not to say that Bungie's references between the two games are not deliberate. The references may not precipitate a crossover with a star-studded roster like Sergeant Johnson and Lord Shaxx teaming up for a free-for-all on the Flood/Hive, but it's still pretty cool to think about.

The reference Bungie is making comes in Destiny 2, with the mission aptly titled "The Whisper." The quest is a timed adventure on Io, with the returning Destiny powerhouse Black Spindle as its reward.

The forum user that discovered the connection this week still seemed pretty hype for a crossover in the near future, even if comments dissuaded them - "Going to be pretty nuts when Savathun activates the Halo, and Mithrax and the Arbiter help us take her down."

This isn't the first time we've seen Bungie add crossovers to their franchises either. When Destiny was first entering into development, the company hid a special easter egg in their ODST title.

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In the level "Mombasa Streets", players can find a poster emblazoned with the slogan 'Destiny Awaits', with an image of Earth sitting beneath the message. Above the image of Earth lies a familiar sphere - the Traveler.

Disappointingly, when Bungie left the Halo franchise and Microsoft took the reigns, the easter egg was removed. Newer releases of the ODST title sees the 'Destiny Awaits' slogan edited into a 'FOR HER' message.

In the first title in Bungie's newest franchise too, the Master Chief earns another mention. Details of "Earth's mightiest defender" is referenced in the Cosmodrome, leading many to believe it's about the Spartan that saved the world from destruction just one franchise ago.

Funnily enough, there's even a building in the first game that looks exactly like the Master Chief. That's too perfect to just be a coincidence.

So what do you think - could Bungie eventually pull the trigger on getting their biggest franchise hero into the Destiny world? Do you think Microsoft wants to team up again with the company that once forged their path into the gaming world? It'd be pretty awesome, no?