Benicio Del Toro has joined the increasingly impressive cast of Marvel’s superhero film, “Guardians of the Galaxy.” Deadline says  Del Toro’s role is being kept tightly under wraps by Marvel’s production team, but it seems likely that he'll play Thanos, the all-powerful villain who appeared at the end of “The Avengers.”

What makes us so sure that Del Toro is set to play Thanos? For one, all but one of the heroes have already been cast. Chris Pratt is set to play the lead, half-human space pilot Star-Lord. Dave Bauista is signed on for the green-skinned alien Drax the Destroyer, and Zoe Saldana will star as (again) green-skinned last-of-her-kind warrior Gamora. The only hero left to cast is the voice of the CGI talking raccoon badass named (seriously) Rocket Raccoon. Del Toro doesn't seem like the right fit for that part.

Similarly, there’s a big hole in the casting of the main villain. Michael Rooker, Lee Pace and Karen Gillan have signed on as villains, but their parts don’t seem big enough to anchor the sci-fi epic. At the same time, Del Toro has signed a multi-film deal with Marvel Studios, and his character is set to be a major part of future Marvel films. We already know based on “The Avengers” that cosmic overlord Thanos is going to be the focus of Marvel’s “Phase Two” movies, so casting Del Toro as Thanos just seems right.

At this point in its development, “Guardians of the Galaxy” has gained enormous hype from fans of the comic book space opera, but it’s been treated with confusion by those outside the comic book community. After all, this is a major motion picture starring a talking raccoon, a sentient tree and a half-human space warrior. It all sounds like a pretty crazy move for Marvel, but the studio is built on seemingly unbankable risks like this.

Remember, in 2008, almost no one outside of comic fans knew who Iron Man was. The armored avenger we all know and love now was little more than a supporting player in Marvel’s Avengers series. And not only did Marvel choose to make “Iron Man” the focus of its first blockbuster, the studio chose to use Iron Man as a jumping off point for its entire interlocking (and extremely profitable) cinematic universe. And it worked.

Against all odds, Marvel made a second-tier superhero one of the most recognizable names in the world, and there’s no reason to think the studio can’t do it again with the “Guardians of the Galaxy.” As long as Marvel sticks to its tried-and-true method of casting fantastic character actors in well-written, special effects-heavy films, “Guardians of the Galaxy” will be a success.

“Guardians of the Galaxy” is directed by James Gunn and set to open Aug. 1, 2014.