Christopher Nolan's Dark Knight trilogy helped usher comic book films into a more grounded era where its heroes and villains felt more realistic than ever before. Aside from villains like the Joker getting this treatment, one of the more surprising additions is the inclusion of Bane in The Dark Knight Rises. In the comics, he can increase his strength thanks to the dangerous steroid known as Venom. However, the film doesn't use Venom to give him the strength necessary to take on Batman. So, let's look at how Bane is able to still operate as if he is infinitely more powerful than the Dark Knight.
In the film, Bane is a villain but also suffers from a handicap that is eventually exploited to help Batman gain the upper hand. He obtained the disability after helping a young Talia Al Ghul escape the pit which housed dangerous criminals. As he watched her rise, he was taken below and beaten so severely he remains in constant pain. However, instead of living with it, he focused his mind and body and became incredibly strong, intelligent and cold-hearted. His tactical expertise would later aid him in taking over Gotham City from the surface while Talia infiltrated from behind the scenes.
During his first fight with Batman, Bane was able to beat Batman nearly to death by hitting on the hero's cowl until it began to crack and breaking his back. While this isn't something that is impossible to do for a normal human, it still takes incredible strength and strain for a person to perform such a feat. But what gives Bane the advantage is that his mask feeds to him mild anesthetics that numb his pain and his ability to feel pain. As a result, he is able to strike with a lower pain tolerance, which allows him to hit faster and harder than anyone else.
Bane's strength is showcased throughout the film with how he kills any members of the League of Shadows who disappoint him or when he faces off against Batman in the streets. However, perhaps the most impressive show of strength is when he lets loose while flurries of fists at Batman, and one of them connects with a concrete column. Rather than breaking his hand, the column gets a massive chunk taken out of it, showing that Bane is relentless and pain is nothing more than an obstacle to be overcome.
In the previous two films, Nolan was able to show a grounded take on concepts like immortality and scarring to create a character like the Joker. But by chipping away at the fantastic, he lets the villains embody their reason for existing. For example, the Joker represents chaos, and he always acts as such. Likewise, Bane represents destruction, and to do this, he no longer feels pain and isn't afraid to make sacrifices to achieve his goals.
Even with his numbing drugs, Bane is no superhuman. But in the world of the Dark Knight trilogy, Bane is imposing enough that his reputation instantly makes his opponents feel weaker. And his natural strength and low pain tolerance reinforce those beliefs with each powerful punch. While Bane's reason for his strength is simple, it leads to massive outcomes and creates an enemy even more terrifying than the Joker.