The characters in relation to Bruce Wayne

[Edd Grayson]

I think all the other main characters are a reflection of what Bruce could have become: Catwoman is Bruce if he let himself consumed by pain and wanted vengeance alone, Schreck if he abused his wealth and power to do evil instead of good, and Penguin if he had used his Batman persona to hurt people.

The differences would be that Schreck has no alter-ego, Catwoman is psychotic instead of being just a recluse and Penguin is naturally deformed instead of wearing a costume, but I think I managed to get the point across.

[Catwoman]

yeah its called something like german expression or something where all the characters reflect the main hero or something. or i think that's how it works. lol.

[The Dark Knight]

I love this stuff and Batman is ripe with it.

Generally speaking here's a few examples from the comics:

Joker: The opposite of Batman. Murder is a joke and mayhem over control.
Two-Face: Dual identities and chance, namely with his origins. 
Scarecrow: Using fear as a weapon.
Penguin: Reflects Bruce Wayne the businessman, but gone bad.
Catwoman: Walking a fine line, neither villain nor hero. Issues with truly settling down.
Riddler: Batman proving he is the world's greatest detective.
Bane: Matching and often surpassing Batman's strength. Though Bane goes too far one way with his devotion to strength, as explored in 'Venom'.
Mr Freeze: Being emotionally cold, especially in terms of making a vow and doing whatever it takes for loved ones.