After joining General Zod's Sword of Rao to overthrow the Law Council, Jax-Ur was captured and placed into the Phantom Zone for treason. When he awoke from his somatic reconditioning, Krypton was destroyed and the prisoners led by Zod were adrift in its ruins. Jax-Ur joined Zod's cause in search of Kal-El and the Growth Codex to Earth where they planned to create a new Krypton but was returned to Phantom Zone when Kal-El's Spaceship was used against Black Zero's Phantom Drive.
Growing up with a ravenous thirst for knowledge, especially in radioactivity, he became a famous scientist among Kryptonians. After Jor-El predicted that Krypton was in danger of destruction, General Zod founded the Sword of Rao movement to overthrow the Law Council and preserve the Kryptonian race in which Jax-Ur joined.
When Zod's coup is thwarted and he and his men are arrested and sentenced to 300 years frozen in the Phantom Zone, this ultimately saves them as Krypton is destroyed by its unstable core soon after. When the planet was destroyed, all of the prisoners in the Phantom Zone are freed, including Jax-Ur. Under Jax-Ur's instructions, they retrofit the Phantom Zone Projector into a Phantom Drive to use to search the universe for other survivors starting with the old Colonial Outposts.
Arrival on EarthEdit
After Kal-El activated an ancient Scout Ship on the planet Earth, Zod and his troops followed the signal and sent a message out across the planet demanding Kal-El be turned over to them otherwise the planet would perish.
Kal-El and the human Lois Lane are brought aboard Black Zero where the Kryptonian atmosphere nulls his powers. He is strapped down and Zod has Jax-Ur probe their minds for information before Zod goes to retrieve Kal-El's Spaceship and the Growth Codex. Lois is placed in a holding cell and releases the Jor-El AI from the House of El Command Key who changes the atmosphere aboard the ship giving Kal-El his strength back. Jax-Ur flees with Kal-El's blood sample in fear.
After battling Kal-El and Earth forces in Smallville, Zod and his men return to Black Zero. Jax-Ur informs Zod that he has located the Codex and that Jor-El disintegrated it into Kal-El's individual cells and that he can extract it. They then release the World Engine before taking Black Zero to Metropolis where piloted by Jax-Ur and others, they activate the gravity beam and begin terraforming the planet.
Col. Nathan Hardy pilots a C-17 containing Kal-El's ship directly into Black Zero where the lightdrive of the two crafts react creating a Phantom Zone portal which sucks Black Zero, the plane and all aboard into the singularity.
See Also: Kryptonian
Had Jax-Ur entered a star system with that of a yellow G-type main-sequence star, then his body would have absorbed the solar energy, tremendously enhancing his strength, and granting him several incredible powers, identical to those of Kal-El, who was raised from infancy on the planet Earth.
- Scientific Expertise - as an illustrious member of the Kryptonian Thinker Guild, Jax-Ur was one of Krypton's foremost scientists, on par with Jor-El. It was under Jax-Ur's instructions that Zod was able to retrofit the Phantom Zone Projector into a Phantom Drive, to use for searching the universe for other Kryptonian survivors. After examining Kal-El's blood, Jax-Ur was also the one to discover that the Growth Codex had, in fact, been fused with all of Kal-El's cells.
- Mackenzie Gray, who portrays Jax-Ur in Man of Steel, portrayed a failed and aged clone of Lex Luthor in Smallville.
- Interestingly, Jax-Ur is the only member of the Sword of Rao not to be from the Warrior Guild, being from the Thinker Guild instead.