The sequel to the Avengers marks the fourth movie for the heroes with solo movies (Thor, Captain America) except Iron Man, which has run its course of three movies. The question about the characters' futures has been raised.

Chris Evans has shared with Variety the story about how Marvel pursued him to play Captain America, and how he will maintain his hardline stance once the contract is due.

Variety reported: "When Marvel approached him with the part four years ago, Evans turned it down - several times. 'The problem was initially, it was a nine-movie contract. And they said, if these movies take off and do very well, and my life changes and I don't respond well, I don't have the opportunity to say, listen, I need a fucking break. That just scared me.'

After testing a handful of other actors, Marvel made another attempt to woo Evans. 'They called back and they tweaked the deal. It went from nine (films) to six. I said no again.' Marvel tried once more, and that's when Evans' reps started giving him a hard time, the actor admits. 'My family was even going, 'Are you sure you're making the right decisions?' It started to feel like maybe this is what I'm supposed to do.'

When will Evans finally hang up the character's shield? 'That's a good question. We can do this out loud. ('Avengers 2') will shoot till August. I wouldn't be surprised if for all of 2015, we didn't do a movie. I bet by 2017, I'll be done.'"

That seems like a safe bet. Cinema Blend cites an interview with Mark Ruffalo, revealing his contract details:

"Mark Ruffalo said that he has signed a six-picture deal that will see him playing the character many more times. This is a deal similar to what Chris Evans, Robert Downey Jr., Chris Hemsworth and Samuel L. Jackson made when they signed on to play Captain America, Iron Man, Thor and Nick Fury, respectively."

Since Ruffalo does not have his solo feature movie, speculation about his other three pictures abound. He could guest in other franchise movies aside from Avengers or he will have his trilogy after Avengers 2.

But the six picture deal expires on Thor and Captain America. Iron Man has lapsed already and current negotiations have gone nowhere.

It was revealed that Sebastian Stan, who plays the Winter Soldier, has a whopping nine picture deal. Don Cheadle, who plays War Machine, will appear in "Avengers:Age Of Ultron." Speculations on Loki becoming the king of Asgard could lead to a spin-off feature with or without the Thunder god.

Big movies make bigger actors, and Marvel understands this. Continuity is important and their refusal to be taken hostage by movie stars requires that they constantly establish newer stars. That's exactly what they're doing.