In pre-Crisis on Infinite Earths continuity, Dev-Em is a Kryptonian juvenile delinquent who survives Krypton's destruction by placing himself in suspended animation in an orbiting space capsule.

Dev-Em returns in Adventure Comics #320 (May 1964), where he has reformed, joined the Interstellar Counter-Intelligence Corps, and become an ally of the Legion of Super-Heroes.

[2] Post-Crisis, the limited series Who's Who in the Legion of Super-Heroes #1 (April 1988) depicts Dev-Em as David Emery, a Titanian who replicates Kryptonian abilities using his mental powers.

Additionally, a human psych ward patient named Derek Mathers is a member of a cult that worships Kon-El, and is known as Devem.

[5][6] In both his Daxamite and Kryptonian iterations, Dev-Em possesses the same superhuman abilities of both races while beneath the empowering light of a yellow sun such as that of Earth's solar system.