Dru-Zod is a megalomaniacal Kryptonian, in charge of the military forces on Krypton. He knew Jor-El, Superman's father, when Jor-El was an aspiring scientist. When the space program was abolished after the destruction of the inhabited moon Wegthor (engineered by renegade scientist Jax-Ur), Zod attempted to take over Krypton. Zod created an army of robotic duplicates of himself, all bearing a resemblance to Bizarro. He was sentenced to exile in the Phantom Zone for 40 years for his crimes. Zod was eventually released by Superman when his term of imprisonment was up. However, he attempted to conquer Earth with the superpowers his Kryptonian body acquired under the yellow sun (the source of Superman's own super-powers). With Zod's threat now obvious, Superman was forced to oppose him and ultimately returned him to the Zone.