Zim is rude, commanding, and quite a jerk when he doesn't get what he wants immediately. He's mean to Gir, and frankly everyone around him. He can show care sometimes, but that's rare. Most of the time, he yells a lot. He is an alien (Irken, in specific) who came to Earth to "invade" the planet, when in reality, The Tallest (the leaders of his planet), just wanted him dead. They could care less for him. Zim is unaware of this, though.