Lex Luthor

Lex Luthor is the main enemy of Superman in the Superman comics and media. He is intelligent and very tricky.

Personality
Lex Luthor is a complete megalomaniac. He seeks to control everything he sees due to a delusional sense of entitlement. With no sense of empathy, he cares nothing for his fellow man and only keeps people alive if they benefit him.

Superman Returns
In Superman Returns, Lex Luthor tries to take over the world by destroying some of the earth and creating a huge land mass which everyone will have to pay a big amount to live there. He sneaks behind Superman's back to an arctic region that Superman often visits, and he finds out how to access the main computer that will tell him anything he wants to know about Krypton. After that, he finds and steals some Kryptonite so that he use it against Superman, knowing that it makes him weak and deprives him of his powers. Also some of the Kryptonite he stole he put in the substance that helps make land. By doing that he was able to make a land mass that Superman would be powerless on. So Lex was able to get in close and stab Superman in the stomach with a shard of Kryptonite. By doing that, he nearly killed Superman and became rich.