I have a fan theory that at the end of Mad Max: Fury Road although Immortan Joe was defeated, his men avenged him by capturing Max and condemning him to an underground prison known as Hell on Earth. To avoid familiar faces in prison Max changed his name to Bane and tried to disguise his voice. In time he does make at least one friend. In a little more time the plague broke out. And shortly after that a prison fight goes down. Bane was able to save his one friend and she escapes. But Bane is left behind and facially disfigured. And one day he is saved from Hell on Earth by the League of Shadows. He did not know who they were or that his friend that he saved had a connection to the league. They took him in and made him one of their own. He did need surgery and a mask to "keep himself together" after the fight.
The league teaches you to confront your fear and use it as fuel to fight for the greater good. For his symbol of fear Bane, who never went by Max again, chose Immortan Joe. The man that, indirectly, condemned him to Hell. Bane's mask is a half face mask that exposes the forehead and eyes; just like Immortan Joe's mask. Which is why that was the best choice for Bane's symbol of fear.
And that is how Mad Max: Fury Road is a prequel to The Dark Knight Rises; not because Tom Hardy plays Bane and Mad Max.