Garlic Jr. is both evil and smart. He has grand plans to take over the universe. He is able to transform into a monstrous ruler. His wish is to ruin Kami, the Namekian guardian of Earth. Then he could rule the Earth. The Eternal Dragon Shenron gave Garlic Jr. immortality after he successfully collected all seven of the Earth's Dragon Balls. Since then he's been locked in the Dead Zone. Garlic Jr. is originally from the Makyo Star and his power fluctuates with the star's distance. When the Makyo Star is close to Garlic Jr. his power increases, pushing him out of the Dead Zone.
When the Gang finds out about where Garlic Jr. gets his power, they destroy the Makyo Star, causing Garlic Jr.'s power to disappear. The gang then sends him back into the Dead Zone forever.