There's still a world of uncertainty with regards to the Iron Man franchise, but some clues are trickling for 'Iron Man 4.' Some possibilities are the return of Trevor Slattery as the Mandarin and Robert Downey, Jr as Tony Stark.

But it is also possible that someone else will wear the armor and that the Mandarin is a separate entity (as suggested in "All Hail The King").

Iron Man arch supervillain the Mandarin, may be re-introduced in "Iron Man 4". We last saw Iron Man's archenemy in the third sequel and the character was played by Ben Kingsley but he turned out to be just an actor (Trevor Slattery) playing Mandarin. In an interview with IGN, the 70-year old actor talked about reprising his role as Mandarin and doing another comic character under Trevor Slattery, who was supposed to be the Mandarin in the Marvel Cinematic Universe.

Kingsley said, "So, it's up to the powers that be to decide whether or not they'd want to introduce Trevor, whether or not they'd want to reintroduce the Mandarin." The English actor also teased, "Has the Mandarin invented Trevor, or has Trevor invented the Mandarin? Which is which?"

He explained, "The Mandarin could be so supremely intelligent that he could have said, 'You know what? I'll invent this actor, and he will be my mask.' You know, which is which? Who's pulling the strings. Now, this is me just free-thinking here, but I would love to revisit that world."

Ben Kingsley continued, "But Trev, bless him, may have made an indelible mark on that world. So everyone might say, 'Is it Trev under there?' So they'd have to approach it quite carefully, and so would I, but I would love to go back to that world, yeah."

It's highly possible that Robert Downey, Jr also wants to return to that world, but the negotiations have not yet been settled. It has been rumored that Don Cheadle, who plays Rhodey/War Machine may don the armor-or it could be someone entirely new.

Casting speculation is already on, but if there will be a new incarnation of Iron Man, it can't be Tony Stark played by a different actor. The next 2 Avengers movies (both of which will probably precede Iron Man 4) will probably paint a clearer picture.

If Robert Downey, Jr does not return to play Tony Stark, who should be the next Iron Man?