The Dark Knight Rises has a character named John Blake in it. Gordon-Levitt is a popular actor and the character he is playing seems to have a small role throughout the film. Once you watch the movie, at the end, there is an ending which totally changes Batman. Wont say what for spoiler reasons. Who do you think John Blake is?
Robin? A new Robin maybe. Or a mixture of Tim, Dick, and Jason. Read the below comments for further details.
Nightwing? John Blake looks like he should be Nightwing instead. Blake isn't a kid and would suit better, in my opinion, as Nightwing.
Catman? Thomas Blake is the original name for Catman... similar to John Blake. It could be his son who proceeds to become Catman. Very unlikely (after seeing the film). Who is to say that Blake wants to be the next Batman? Maybe take on a whole new thing as Catman? Catman and Batman do rhyme! :p
Azrael? Could be possible. Even after seeing the movie, I will not dismiss this. Azrael has received much attention for people believing Blake is him. But I find it unlikely.
Next Batman? This is very likely. I will not mention the end of the movie but the ending suits well with this. I am not much of a fan of this idea but it is possible.
Any other possibilities? Who do you think it is?