The "Man of Steel" sequel will not just feature Superman, but it is an entry into the construction of an entirely new DC Universe. What DC Universe would be complete without Batman?

In the new characterization of Batman, there are some plausible fan theories (which means it can be entirely true or completely ridiculous) that merit some attention. While these were only inferred in the Christopher Nolan trilogy, the eventual Batman reboot (assuming there would be one) could explore these further.

Alfred the Butler is Bruce Wayne's Real Dad

Wayne Manor may have more secrets than we ever care to discover. One of them may be the true connection between Alfred and his ward, Bruce Wayne. This theory has a rather cynical but realist feel to it, taking down the picture of perfection that Bruce Wayne had of his family, or Alfred's undying and selfless devotion. This theory has circulated and been discussed on Reddit and What Culture.

Alfred will probably be the most loyal butler ever, staying with his ward for the rest of his life. We would presume correctly that Alfred is paid rather handsomely by the Wayne estate. It is also common for butlers/nannies/ etc to develop an attachment to their wards, especially when they're orphaned.

Alfred was seen as the surrogate father figure to Bruce Wayne, but is it possible that this is more than a 'figure?' This will desecrate the character of Bruce Wayne's mother and Alfred, but given that the senior Wayne is busy running a corporate empire and Alfred was formerly of the British Intelligence agencies (that produced James Bond) it would not be so far-fetched.

In the Dark Knight version of Alfred, he is not at all bumbling, and was given a background that he was a former spy/secret agent. It is easy to explore other opportunities given that background. Why would he stay as a butler? His concern for Bruce is fatherly and Bruce also left the entire Wayne estate in his name when he left to train with the League Of Shadows.

Definitely not the usual employee/employer relationship.

The Joker As A War Veteran

The inspiration for this theory (as discussed in Reddit/Cracked/What Culture) is the Joker (in The Dark Knight, played by Heath Ledger) always asks the question "You wanna know how I got these scars?"

The Joker gave two different versions on how he got the scars, which means that neither was true. However, a statement he mentioned to Harvey Dent while he was in the hospital: "A truckload of soldiers will be blown up, nobody panics because it's all part of the plan."?

The statement may be a clue of why the Joker was driven into madness, as he was telling this to Harvey to drive him into madness (which succeeded). The War veteran theory will also explain why the Joker is a master strategist, why he knows so much about the criminal justice system and how he was able to disguise himself seamlessly as a soldier. It is also the rationale for his anger towards the government/authority.