Origin of the Phantom Zone
But, this opened a Pandora’s Box of problems, as the criminals were now aware of Earth, Superboy and would work tirelessly to get themselves free and subjugate the Earth, and the son of Jor-El, the scientist who found the zone, and put most of them there.
A few of those prisoners Superboy saw in that first appearance were Dr. Xadu (a scientist sent to the Zone for conducting forbidden experiments in suspended animation which resulted in the deaths of his patients, and his wife, Erndine Ze-Da, was later sent there as well, and the pair menaces Superboy and Superman at different times), but the most important prisoner was General Zod.
Zod In the Zone
Jax-Ur Gets Free
The Female Is Deadly
Hero In The Zone
The Zone Is the Star
Some of these Kryptonians had to have sentences that elapsed between the time of Krypton’s destruction and Superman’s life span…and that was the case for Quex-Ul in Superman #157 (November, 1962 by Edmond Hamilton and Curt Swan). In this story, Superman freed Quex-Ul, who was then plotting revenge on Superman as the son of his jailer, and Superman even ended up proving the Zoner was originally innocent (having been hypnotised into believing he was guilty). After being informed of his innocence by Supergirl, Quex-Ul trips his own gold kryptonite trap on himself to save Superman (thus losing his powers forever)…and Quex-Ul even loses his memory in the process, but Superman helps him, by setting up a life for the Kryptonian as Charlie Kweskill, an employee of the Daily Planet.