Back during the infancy of the Marvel cinematic universe, the viewers were introduced to an emissary of the undercover organization known as S.H.I.E.L.D. named Phil Coulson. When the character first debuted in the final scene of Iron Man, the fans had no idea that this no-name government lackey maintaining a cover-up would have such an important role in the plot narrative of the entire Marvel Cinematic Universe. Not only was Coulson the liaison of each Avenger to S.H.I.E.L.D., he was also the rallying point when he inspired the heroes into co-ordinated action against the sinister movements of Loki. The death an resurrection of Phil Coulson is exactly what triggers the start of the events of Agents of Shield.
A team of agents is led by Coulson to deal with on the ground threats and neutralize any subplot elements that Marvel needs to develop the series plot. The wet work team, that’s what the Agents of Shield are. With the advent of the first season of the series, we were introduced to gravitonium and the good doctor who falls into a whole vat of the stuff teasing the arrival of Graviton.
Graviton is an Avengers level villain who holds the power to destroy the earth itself. To tease such a character in the first season of a TV show like the Agents of Shield was massive for fans. It inspired all kinds of theory and hype until it was completely shut down by the subsequent narrative of the show. Ever since that episode in season one of the series we have neither heard nor seen anything that might remotely relate to the graviton , that is up until the current season of the show.
In the season 5 of Agents of Shield, we find our favorite band of characters 90 years in the future on a desolate earth. The earth is a barren wasteland ruled by the Kre with an iron hand and the rulers have no respect for the inferior life forms that they rule. A good part of season five of the show was spent showcasing this earth and subsequently freeing this version of the earth from Kreme domination.
For the first half of the season the Agents have worked against the ,elder Kaicus to make sure that the future remnants of humanity have a surviving chance when our heroes return to the present and determine why the earth is so desolate in the first place vis a vis what kind of monster could it be who makes the earth so. During the events of the season, we see Fitz seal the breach to a fear dimension by using gravitonium. This is a massive hint and has sent the fans into a frenzy. The prevailing theory being that gravitonium only has a finite quantity and the mass of gravitonium exists only near the original owner of the substance I.e. Graviton. This being is an amalgation of existences, a creature that is neither human nor alien, it is just a sentient being hell bent on destruction.
It’s entirely possible that after bringing back gravitonium into the fold, Graviton finally makes his appearance in the Marvel Cinematic Universe, giving the Agents of SHIELD the biggest threat they have ever faced. A planet buster vs a handful of human beings with above-average abilities. The premise sure seems very compelling and everyone likes to vote for an underdog. The idea of Graviton being the final foe for presumably the last season of the series also seems viable because Graviton has the ability to level e earth and leave it in the state that we see the planet in at the start of season five.
The only question is how will Coulson and the other Agents defeat Graviton without enlisting the help of the Avengers. Ere is no one left to support the Agents and this task must be fulfilled, the earth must be protected from all threats, that is the job that Agent Coulson was entrusted to. The Agents must deal with the threats on the ground and keep fighting no matter how hard things get.