Despero has a tall muscular figure with vivid purple skin. He has a squat head with no hair, instead sporting a large fin in the middle. Notable features in his face are the absence of a nose (and any nasal cavities) and a third eye above the other two, though he keeps it closed when he does not use it to access his powers.
As a gladiator, he has battle-armor ranging from his left shoulder to his entire right arm.
L-Ron teleported Despero to the Hall of Justice to combat the heroes residing in the building. After immediately knocking Captain Marvel through the glass door, Despero mesmerized Zatanna to prevent her from using magic against him. Despero advanced on Captain Marvel, until Billy used his transformation lightning against him, ultimately revealing Captain Marvel to be a child. Disappointed by this realization, Despero mesmerized Billy before switching his target to Superboy. Egged on by L-Ron, Despero quickly defeated Superboy and attempted to remove his head, until Bumblebee got his attention by stinging his third eye, while Despero simultaneously sent her into a trance. Before he could crush Bumblebee, Mal Duncan as the Guardian arrived to distract Despero, until Superboy recovered. The three continued to fight, until Despero became aware of the diversion, and attempted to mesmerize Guardian. Zatanna used Miss Martian's mind link to possess Mal and reflect the psychic attack, rendering Despero motionless. Superboy took the opportunity to knock the defenseless Despero through a wall.
After the Reach ambassador removed the force field surrounding the Hall of Justice, the Reach took custody of Despero. At some point, he was imprisoned in a stasis cell, and later moved to the Warworld after the Reach gained control of some sections.
Despero possesses immense strength and endurance, and is considered the strongest fighter in 92 star systems. His third eye, located above the other two, allows him to put people in a catatonic state. He is able to understand spoken English, backing down after L-Ron instructed him not to continue fighting against Billy Batson or Mal Duncan.
Invulnerability: Despero exhibits a high resistance to damage from physical blows by Superboy and Captain Marvel, a telekinetically thrown statue of the Martian Manhunter, and Bumblebee's (admittedly-weak) stingers.
Magic invulnerability: Captain Marvel's transformation lightning did not severely affect Despero.
Stamina: Despero engaged several Justice Leaguers and Team members in physical combat without exhibiting fatigue.
Third eye: Despero's third eye gives him the psionic power to mesmerize others into a trance-like state.