Marvel Phase 3 will showcase the last movies of the major trilogies - Iron Man, Thor and Captain America. Plans to make solo films for the other Avengers have not been confirmed so for Vin Diesel, who has teased a Marvel project in 2016, it could be a new character.

Nobody wanted to believe Vin Diesel when he said that he will play the voice of Groot-all three words of it. It was officially announced but the point is, he would probably play another character. After all, you don't sign a franchise builder like Vin Diesel and let him go after one film, let alone not using his screen presence.

Here's a look at the possible characters that Vin Diesel could play. Thanos has already been discussed so we can have other suggestions.

Adam Warlock is Thanos' nemesis. He was a short-lived hero, but during the time they built up Thanos, he was the one who defeated him. It is quite a surprise that he is not even hinted in Guardians of the Galaxy. Perhaps it is Marvel's best kept secret.

From Comic Book Movie, it was pointed out that there is actual evidence, or at least an easter egg in the "Thor: The Dark World" credits scene. A cocoon was shown, which, in the comic story arc, is where Warlock emerged from. Of course, it is still speculation on whether it is THE cocoon, but of all things they had to choose that object. Hard to believe it's just a coincidence.

Other candidates would be Black Bolt, the leader of the Inhumans. Marvel would like to showcase their creativity in conceptualizing superpowers but they could not explore that fully the way Fox does with the Marvel mutants. The Inhumans would be the only way to have the Avengers battle a super powered group without having to introduce individual back-stories.

Newsarama has already explored this possibility: "Back in March 2011 there were reports that a script was being developed, and in November 2012 Stan Lee confirmed this was in development.

Picturing Vin Diesel playing the near-mute Black Bolt seems perfect, relying on his on-screen presence and using his deep voice sparingly but to great effect. Also, Diesel works well in ensemble films as seen inFast & Furious, and could work great with characters like Medusa, Karnak, and the loveable Lockjaw."

Two more candidates who have the significance that an A-lister like Vin Diesel can command. Which one would you like to have?