Ever since he took the Groot role in Guardians of The Galaxy, actor Vin Diesel has been hinting to a second Marvel role. Diesel has been pointing to a large part in Marvel's Inhumans film. That was announced by Marvel in October for a November 2018 release date. He took to Facebook and posted this image, clearly teasing involvement with Inhumans.
We've suspected for ages he could be up for the role of silent leader Black Bolt. Giving his voice to Groot and his body to the Inhuman, a way for him to play two roles.
Marvel has been planting seeds for the film with the finale of Agents of SHIELD. It's also expected to see the origin of Scarlet Witch and Quicksilver in Age of Ultron reflect their possible Inhuman connections, which are now being teased in the comics.
The cast for the film might be on the level of the X-Men films, since there a bunch of Marvel characters the studio could make Inhuman. Instead of explaining their extensive or wacky backstories, just pegging them as Inhuman could help build a world as big as the X-Men universe. Characters like Tigra and Quake will be Inhuman, but it's unknown if they'll make the film.
We know that Namor The Sub-Mariner was originally a mutant, but if Marvel figured-out a deal with Universal (sitting on the film rights) they could use character as a focal-point in an Inhumans film. Having the Atlantean a splinter royal family within the Inhumans group. Kevin Feige confirmed to IGN during the summer that indeed a deal of some sorts would be need to be worked-out with Universal. Since, we've seen Marvel try to work things-out with Sony there's a strong possibility Namor could join the MCU. Let's face it, Universal isn't making a solo film anytime soon and they'd get a hefty loan fee for Marvel to use Namor.
It’s slightly more complicated than that. Let’s put it this way – there are entanglements that make it less easy. There are older contracts that still involve other parties that mean we need to work things out before we move forward on it. As opposed to an Iron Man or any of the Avengers or any of the other Marvel characters where we could just put them in.
SOURCE: VIN DIESEL