Fans have known for quite some time that Marvel Studios' upcoming Thor: Ragnarok would use part of the iconic Planet Hulk storyline from the Marvel Comics, since, due to a complicated rights issue with Universal Pictures, which distributed the 2003 Hulk comic book adaptation, the MCU can't have a stand alone Hulk movie. Instead, parts of that story were carried over to Thor: Ragnarok, and in a new interview, Marvel Studios president Kevin Feige shed some light on why this particular story was used for this Thor movie. Here's what he had to say, revealing why other new characters like Valkyrie (Tessa Thompson) were introduced in this movie.

"Because when we were thinking about what other Marvel players to bring into Thor's story, which was important to us, it was important to Chris (Hemsworth), he had looked and seen Captain America get Black Widow and Iron Man, and all of these other players and he goes, 'Mate, who's coming into my movies?" And as we were thinking about that, number one, with Thor, more so than any of the other players, he's got an amazing cast of characters in his books. So certainly, one of your questions about Sif, I'm jokingly pushing aside, but really it was we wanted to see Valkyrie in this movie. We wanted to introduce Hela in this movie, and there's Balder and there's Beta Ray Bill and there's still people we haven't done yet because he's got such a great cast of characters. But in terms of other Marvel characters we kept thinking about how fun it would be if we took our two most heroic, most powerful characters, Thor and Hulk. Pit them against each other and but also play the humor and the fish out of water humor between Thor and Banner. And that lead us to, maybe that plane at the end of Ultron did go into space, and maybe this is a chance to see Gladiator Hulk."
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As Kevin Feige mentioned, we last saw Hulk stealing a Quinjet at the end of Avengers: Age of Ultron, heading for parts unknown, since he was convinced he couldn't control his Hulk powers anymore. How and when he ended up on the gladiator planet of Sakaar remains to be seen, but this is where he ultimately became the planet's gladiator champion. We also know that things haven't been looking so great for Thor, with the nefarious Hela (Cate Blanchett) banishing the God of Thunder from his home realm of Asgard, while also destroying his hammer Mjolnir. There has been indication that Mjolnir will return in some way in Avengers: Infinity War.

What also remains to be seen is how much of Hulk we'll see, and how much of Bruce Banner we'll see. Mark Ruffalo revealed in an interview last year that Bruce Banner and the Hulk will be on a "collision course" with each other in this movie, but we have seen in footage that Bruce Banner does ultimately surface on Sakaar, in a scene where he's clearly frantic, asking Thor where they are, since he has been completely in Hulk form for the past two years, since disappearing with the Quinjet. This also explains the "baby talk" that fans saw in the trailers, since Hulk has now learned how to form sentences.

While this movie is expected to be the last stand-alone Thor movie, Mark Ruffalo revealed in another recent interview that this story will actually be the start of a Hulk trilogy of sorts, which will be continued with Hulk's arc in next year's Avengers: Infinity War and 2019's Avengers 4. The actor wouldn't shed any light on the Green Goliath's arc in those next two movies, but it certainly seems that fans will be getting more out of the Hulk and Bruce Banner story than they have in past Marvel movies. Unfortunately, Kevin Feige wouldn't shed any light on this trilogy in his interview with Screen Rant, but hopefully we'll find out more as the stars and producers continue to do press for Thor: Ragnarok as we get closer to the November 3 release date.