The Avengers have a solid cast and good chemistry. That was  the appeal of their $1.5 billion box office return. Other super hero movies like "X-Men: Days of Future Past" have taken a different approach, to place as many characters as possible.

"Avengers: Age Of Ultron" needs a mix of both. They cannot have just the same characters, as they need to introduce new players based on the direction of the entire Marvel Cinematic Universe. The Scarlet Witch and Quicksilver have been introduced. Now, it's the Vision.

The first report came from The Daily Mail UK:

"British actor Paul Bettany has joined the elite super-heroes the Avengers and is in training to bring a comic book warrior out of the cold and onto the big screen.

Bettany will play the Vision, an old-timer in the world of illustrated heroes, in the second Marvel Avengers movie, Age Of Ultron."

The report was not based on any official statements from Marvel. The Daily Mail only pieced together clues with regards to the actor joining Jeremy Renner (who plays Hawkeye in the movie) in Shepperton Studios, where the Avengers shooting is taking place.

The quote from The Daily Mail:

"The casting of Bettany has been shrouded in secrecy, but he was spotted at Shepperton on Monday. The Avengers: Age Of Ultron is code-named After Party . . . or at least it was."

Bettany is known as the voice behind Jarvis, the virtual butler of Tony Stark in the "Iron Man" series. There were rumors and speculation that spread around that Jarvis might become Ultron, due to teasers from Marvel where Iron Man's cowl turned into the Ultron's robot face. But those rumors were quashed when Marvel announced James Spader to play Ultron. Nevertheless, Tony Stark has some involvement in the creation of Ultron even if it's not Jarvis.

In the comics, Ultron was created by Henry Pym, the original Ant-Man. But Henry Pym is just about to be introduced in the "Ant-Man" movie, played by Michael Douglas. Marvel Studios has already changed some of the origin stories of their characters, and it is interesting how they would approach Vision, since the actor who plays him is Jarvis' voice.

Did Tony Stark create them both? Screenrant has some clues:

"It's too early to tell if JARVIS and Ultron are both the result of the same event, fracturing Stark's trusty A.I. ally into a light and dark side, or if the butler gains a fighting form to offer his human allies a better chance of survival. We doubt that mystery will be solved prior to the film's release."