Zaltar showing Kara the Omegahedron.

The Omegahedron is a mystical Kryptonian device with magical properties. It was used as the power source for Argo City.


The Omegahedron was "borrowed" by Zaltar, a city official, who showed it to Kara Zor-El. Kara ended up losing the Omegahedron which ended up on Earth. Zaltar fell on his sword and took responsibility and he was sentenced to the Phantom Zone. Kara travelled to Earth to recover the Omegahedron, which had been discovered by Selena, a black magic witch. She used the device to help cast real spells. After battling her multiple times, Kara, as Supergirl, regained the Omegahedron and returned it to Argo City where it once again powered the settlement.