Guardians of the Galaxy is only one month away from its release in theaters, and we still haven't seen all of the main characters revealed just yet. Its obvious that James Gunn is keeping a few secrets locked away until opening night, hoping to please hardcore fans of the comic book. Some of these details are rumored to have already leaked. We're definitely in for a surprise or two, that's for sure. And those familiar with the original Marvel comics know that not every member of this particular Guardians lineup has made it to the big screen. That's what sequels are made for! But still, a few fan-favorite Marvel characters may be lurking around the edges of this sci-fi saga, looking to make a cameo at some point during the movie's runtime. Who might they be? Well, we know Nathan Fillion is playing one of them. Let's take a look at a few familiar faces that might pop up for a surprise appearance before end credits role on Guardians of the Galaxy, and maybe even after.

1 Nova (aka Richard Rider)

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Not to be confused with Nova Prime Rael, played in the movie by Glenn Close, Richard Rider is a member of the intergalactic police force known as the Nova Corps, for which he gained superhuman abilities including enhanced strength, flight and resistance to injury. It was first rumored that Richard Rider would be appearing in Guardians of the Galaxy's post-credits sequence played by Nathan Fillion. While director James Gunn claimed that Nathan Fillion's role as Nova was greatly and entirely exaggerated, he never said that the character himself wasn't showing up in the movie. Nova is an ally of the Guardians, and is the one who helps them set up their base of operations on Knowhere. We've seen photos of Knowhere, and it was revealed in the trailer to exist as a giant floating head of a celestial being. Odds we'll see Nova in Guardians of the Galaxy? 80%.

2 Cosmo

Cosmo <strong><em>Guardians of the Galaxy</em></strong>

Cosmo is also very important to Guardians of the Galaxy's Knowhere base, and its been rumored, never denied, that this is the character Nathan Fillion is actually playing. He is suspected to voice this motion capture mutt, an intelligent, telepathic dog who resides as Knowhere's chief of security and works closely with the Guardians. Cosmo assigns special "passport" bracelets allowing instantaneous transportation to and from anywhere in the Universe via the deceased Celestial's "Continuum Cortex," located within the brain-stem of Nowhere, from where sensors can also detect subtle disruptions in space-time occurring outside The Rip in the greater Universe. Both Richard Rider and Cosmo are quite attached to the space station, and it almost seems impossible to have Knowhere in the movie without at least bringing Cosmo in for a cameo. Odds we'll see Cosmo in the movie? 98%.

3 Iron Man

IIron Man

It has long been rumored that Iron Man will be showing up in the final moments of Guardians of the Galaxy, using his Mark 39 Gemini Sub Orbital Suit to fly into the outer reaches of the galaxy, where he teams up with Star-Lord and his merry team of mercenaries and thieves. It was originally teased that Tony Stark was the key to tying The Avengers franchise together with this Marvel space epic. He did, after all, become an important part of the team in the comic books, fighting alongside Drax, Groot and Rocket. But as we learned earlier this week, that may not be the case. /planet-hulk-storyline-may-be-used-in-guardians-of-the-galaxy-2/Hitfix, who visited the set of Avengers: Age of Ultron, learned that the ending of this upcoming sequel will actually launch Hulk into space in a bid to save the world from Ultron. This sets up Guardians of the Galaxy 2, and supposedly reworks some of the elements of Planet Hulk so that Star-Lord and the others can participate in Hulk's gladiatorial pursuits before guiding him back to earth. But that leaves a hole in the first Guardians of the Galaxy, which is required to somehow tie into the Marvel universe on some level. Maybe that level is purely tied to the appearance of Thanos. Or maybe one of the Avengers will show up on screen in some capacity. Odds Tony Stark will show up to greet Star-Lord and welcome him into the Avengers fold this time out? 36%.

4 Phyla-Vell (also known as Quasar and Captain Marvel)

Phyla-Vell <strong><em>Guardians of the Galaxy</em></strong>

Another character long rumored to be making an appearance on the big screen soon is Captain Marvel. Though many believe she is going to be introduced with a very tiny cameo in Avengers: Age of Ultron. It's also believed that the Captain being brought into the Marvel Cinematic Universe is former Ms. Marvel Carol Danvers. But what if they went with Phyla-Vell instead? She is one of the 2008 Guardians that joined on with Star-Lord in the comics, but her very storied history might have been what kept her from becoming a part of this live-action retelling. She has gone by the names Quasar, Captain Marvel and Martyr in the past, with her complex biography maybe too complicated to tell on the big screen. Its not an easy character background to digest in one setting, and Phyla-Vell accomplished quite a lot on her journey throughout the cosmos before ever teaming up with Drax and the rest of the gang. It's hard to believe she won't be mentioned in some capacity. But it's very doubtful that the team at Marvel will go with this particular iteration of Captain Marvel. Though, the lesbian angle might be too hard to resist. Odds of Captain Marvel showing up to fight alongside Drax? 12%.

5 Adam Warlock

Adam Warlock

Like Phyla-Vell, Adam Warlock has a very long and storied history in the Marvel galaxy, and he was also part of Star-Lord's original Guardians team lineup. But Adam Warlock is why they make sequels, and while his name might get thrown around on screen this August, we probably won't see him in the flesh until Hulk also comes into the picture. His story is closely tied to events surrounding Phyla-Vell before either character makes their way into Star-Lord's camp. His time with the Guardians is marked by his mission to fix the space-time continuum, a subplot that could seemingly find its way into Guardians of the Galaxy 2 (or maybe even The Avengers 3, how else are they going to stop Thanos?). But bringing him into the first movie would just clutter up the atmosphere. Odds Adam Warlock will join the team in this introductory installment of the Marvel movie franchise? 2%.

6 Lylla (Rocket's girlfriend)

Lylla <strong><em>Guardians of the Galaxy</em></strong> photo

Guardians of the Galaxy may be the first movie in history to feature a gun-toting Raccoon, a brilliant astronaut dog, and a sexy sentient otter. Lylla is Rocket's soul mate, and was already teased in the very first trailer released way back in 2013. She hails from Halfworld, the daughter of toymakers, and has sworn never to leave Rocket's side, despite her penchant for being heavily pursued by other suitors. While the Guardians of the Galaxy movie has already acknowledged her presence, and that she in fact does exist in the Marvel Cinematic Universe, its unclear if we'll see her in the flesh or not. If there are flashbacks or any nods to Rocket's past, we'll surely catch a glimpse of her, even if it is a fleeting one. Odds that Lylla will show up on screen this summer? 68%.

7 Vance Astro

Vance Astro <strong><em>Guardians of the Galaxy</em></strong>

Finally, we come to Vance Astro, a member of the original 1969 Guardians of the Galaxy team lineup. Known as Major Victory back in the day, his declaration inspires the as-yet-unnamed gang of murderers and thieves to adopt the Guardians of the Galaxy moniker for their own. He only needs a brief introduction. And it seems like James Gunn may stick to the source material when it comes to this tiny piece of trivia. Why wouldn't he? Odds we'll see Vance Astro give the Guardians their name? 87%.

Of course, we left out any mention of Mantis, another member of Star-Lord's original team in the comic books. It's easy to see why she got shuffled off to the sidelines of obscurity. A movie only needs one green chick, and she would have confused those not familiar with this universe. Then there's Bug, originally one of the Micronauts. He's almost as cool as Rocket Raccoon, but he definitely won't be mentioned in the first movie. He's sequel material all the way.

B. Alan Orange at Movieweb
B. Alan Orange