I'm not the first person to consider this theory, and there are a few things that lend it credence. First, let's quickly recap what we know about Skye's background — it's not much. It turns out S.H.I.E.L.D. wanted her to move between foster homes as a way of keeping her safe, because of the way in which she was found. When Skye was a baby, S.H.I.E.L.D. agents were called to an 0-8-4, or "object of unknown origin" in China. Most of the S.H.I.E.L.D. agents on the scene were killed and the entire village was destroyed by two "monsters," but a baby survived and was sent to an orphanage. The baby was Skye and as more details of the story were revealed, we learned that those monsters were actually her parents.
The Kree connection also makes the Inhumans a likely fit for Skye. Another big mystery in Agents of S.H.I.E.L.D. surrounds the blue alien that GH-325 — the drug that saved both Coulson and Skye from death — is made from. Though clearly in a state of decomposition, the alien resembled Kree. This relates to yet another mystery on the ABC series, why Skye wasn't affected by GH-325 the way Coulson was. Perhaps it's because she already contains alien DNA and was created by the very creature whose own... something saved her.
I know, it's a lot. But it would make sense. And there's one more reason that Skye might be an Inhuman that is extremely easy to understand: it would unite the Marvel Cinematic Universe. The Avengers franchise and Agents of S.H.I.E.L.D. all take place within the same expanding storyline, with shared characters and the actions of one film affecting another, as well as the TV series. If the alien used to create GH-325 is a Kree, that connects Agents of S.H.I.E.L.D. to Guardians of the Galaxy, the only film to seem almost completely removed from the rest of the universe. If Skye is an Inhuman created by Kree, that's an even more direct connection between the show and Guardians.
Oh, and there's one more kind of important thing. Marvel is rumored to be making an Inhumans movie. According to Collider, there is a script for an Inhumans movie and the studio is just looking for a director. And what better way to get people excited for a new Marvel franchise than to reveal that a pre-existing character is an important part of its story? Besides, Marvel has to find some way to connect Guardians to the rest of its films, since it wasted the post-credits scene on an unnecessary Howard the Duck reference and Coulson didn't make an appearance.
Hopefully Season 2 will finally reveal Skye's real background, or at least give some more definitive clues. The Inhuman theory is certainly promising, but Marvel has created so many species that have gone through such different things in various comic storylines that really, anything is possible. The only thing that's fairly certain is that eventually, Guardians will somehow be pulled into the rest of the Marvel Cinematic Universe and if it can't be Skye who connects them, there's only one other acceptable alternative.
I have a feeling that Baby Groot would fit in just fine on The Bus.
Images: ABC (2); Giphy (3)