Lightning Lad, alternatively known as Live Wire and also known by his real name as Garth Ranzz, is a superhero from the planet Winath living in the 31st Century. He's one of the founding members of the Legion of Super-Heroes, along with Cosmic Boy and Saturn Girl.
Many years later, his son had taken over as Lightening Lad. Along with the sons of Cosmic Boy and Saturn Girl, this new Lightening Lad traveled to the past to invite Supergirl to join the ranks of the Legion. However, she failed her entrance test. ("The Three Super-Heroes!")