When he grew older Robert was given a costume and a pair of powerful energy-band bracelets, and returned to Earth in the 1950s to battle crime.

When the Crusader lost control of the energies channeled through his power wrist-bracelets, referred to as Quantum Bands, they overloaded, and he was vaporized.

This individual was intended as an unquestioningly loyal servant of the Uranian Eternals, conditioned to obey them and to believe he was actually the original Marvel Boy.

However, the plan went awry when a disaster destroyed his creators midway through the project, leaving the Crusader in a deranged and delusional state.

He wore polarized contact lenses which protected him when he manipulated light, creating blinding bursts to incapacitate his opponents.

The full extent of this remains unrevealed, although it is known that he must breathe an atmosphere akin to the planet Uranus' and that, in order to eat, he must distend his esophagus.

Grayson is an accomplished athlete and completed advanced studies of science and technology at the Uranian Academy, giving him knowledge well beyond what has been discovered on Earth.

[volume & issue needed] The parallel universe anthology What If #9 (June 1978) showed a world where Marvel Boy was a member of a team of 1950s "Avengers.