Validus is the most powerful member of the Fatal Five, and one of the most powerful beings in the universe. He is stronger than Superman and seemingly impervious to harm. In addition to his strength and invulnerability, Validus possesses the ability to project mental lighting from his head, a combination of powers from his parents, Lightning Lad and Saturn Girl. Validus was stolen from his mother's womb by Darkseid, and mutated into the beast who would become an enemy of his parents' team, the Legion of Super-Heroes. Darkseid did this to gain revenge against the Legion, who had defeated him during the Great Darkness Saga.
Validus created by writer Jim Shooter and artist Curt Swan.
Original Continuity: New Earth
Validus joined his teammates in the Fatal Five when they were recruited to help the LOSH combat the Sun-Eater. Tharok learned that he could control Validus, and used him to maintain his leadership of their evil group. Validus never seemed to be truly evil himself, but was often confused and manipulated by Tharok and others. Validus famously killed the original Invisible Kid on one of the darkest days in Legion history. Later, through the efforts of his parents, Validus was transformed back into his childlike physical state and he was renamed Garridan Ranzz.
In the post-Zero Hour continuity Validus appeared again, though it was never clear whether this version of the character was also a mutated Garridan Ranzz. This Validus was also a member of the Fatal Five, though he did not appear to be as powerful as the pre-Crisis version of himself.
Threeboot: Earth Prime
In the threeboot Legion continuity Validus appeared once again as a member of the Fatal Five, this time traveling back in time to fight Batman and the Blue Beetle before being taken into custody by the threeboot Legion.
Retroboot: New Earth
A Validus also joined Superboy Prime's Legion of Super-Villains, though it was not clear which version of Validus this was. Most recently Validus has appeared again to once more join the Fatal Five. But Garridan Ranzz still exists in this continuity as a normal child, so how they both exist at the same time is a point of confusion.
Justice League Unlimited
He appears in JLU, battling Supergirl, Green Lantern John Stewart, Green Arrow and the Legion of Super-Heroes. He has a robotic body.
Superboy & the Legion of Super-Heroes
He also appears in the Legion of Super-Heroes animated series. In the second season he joins Imperiex.