Some of Batman's most iconic enemies are actually the personification of one aspect of Batman's character turned up to psychotic levels.
Ra's al Ghul -- sense of righteousness. Batman was someone who would go to whatever lengths to serve his form of justice. And Ra's al Ghul founded the League of Assasins to bring balance / justice to the world.
Scarecrow -- make people fear. Batman's moniker was basically a theatric, making people fear him. Scarecrow used hallucinogens to cause people see what they fear.
Riddler -- high intelligence and mysterious. Batman was genius-level intelligent. So was Riddler. And Batman played on the mysterious nature of his existence to stay in the shadows. Riddler worked around mysteries and riddles to fool the police and give Batman a hard time
Two-Face -- split personality. Batman was a serious, no-nonsense person who fights crime with all his strength, mind, and wealth. Bruce Wayne, his alter ego, was a playboy, eccentric billionaire. Two-Face was a former District Attorney who got split personality disorder.
Bane -- super-human strength. While Batman was not Superman level, he was depicted as stronger than most humans in the DC universe. Bane used "PEDs" to go above and beyond super-human strength.
Joker -- psychologically broken. Batman's childhood trauma permanently broke him. He never really let go of the psychological trauma, he was just high-functioning. While he took the right side of justice, Joker chose the opposite, murderous side.