The Inhumans were a critical part of the 2008 Marvel cosmic revival that included Guardians of the Galaxy. King Black Bolt, Medusa, and the rest of the Inhuman royal family crossed over with the Guardians during the War of Kings event. They are not exactly critical to the Guardians' story, but they could be an important piece of Marvel's future film plans. Marvel is pushing the Inhumans really hard right now in the comics. In the aftermath of last year's Infinity event, new Inhumans are popping up all over the world. It is possible that emphasis could transfer to film as a substitute for the mutants the studio does not have the movie right to. For all we know, Quicksilver and Scarlet Witch will be of Inhuman origin in The Avengers: Age of Ultron since their mutant lineage is off limits. Guardians of the Galaxy is the ideal opportunity to at least introduce the concept or presence of Inhumans. Even if Quicksilver and Scarlet Witch have nothing to do with it, the Inhumans could be major players in the cosmic realm of the Marvel Cinematic Universe. If Guardians proves to be a smart gamble by Marvel, the Inhumans could very well be the next new franchise to add into the cosmic mix.
