Approximately 18,000 years before the Kryptonian Civil War, Kara Zor-El and her classmates were in a training exercise retrieving beacons on behalf of the Explorer Guild in the Kryptonian jungle. Kara explained that the exercise is about preparing for unknown and potentially hostile planets during their space exploration mission.
After traversing through the rigorous landscape, Kara sent Nam-Ek and Dora to the south, her and Thara to retrieve one of the beacons, and sent Kell-Ur, her boyfriend, and Dev-Em to retrieve one of the beacons. Dev-Em angrily questioned her authority, but Kara dismissed him and sent them off. As Kara located the beacon, she heard the screams of Kell-Ur, who was about to fall off a cliff.
As she tries to help him up, a snake bit his hand and Kell-Ur falled to his death. Dev-Em arrived from behind whom Kara accused him of murder. Dev-Em tried to kill Kara with his machete, claiming that since only four students would have graduate, killing the others would had greatly improve his chances. However, Kara quickly disarmed and subdued Dev-Em to be arrested by the Kryptonian Law Council.
- "Your blatant disregard for the life of your fellow students is troublesome."
- ―Dar-Enx to Dev-Em[src]
Taken to Kandor, the Law Council declared Dev-Em guilty of assaulting Kara Zor-El and murdering Kell-Ur, the first murder on Krypton in a millennium. They initially invoke the death penalty, but after protests from other council members, they decide to imprison Dev-Em indefinitely.