Leta Lal was the daughter of Jhor Lal, leader of a group of people fleeing cruel tyrants of the planet Vruun, who came to colonise Earth in the distant past, founding the city of Atlantis. They came into conflict with another group of colonists, led by Zat-El, from the planet Krypton. After initial hostilities, the conflict was settled when the Legion of Super-Heroes found that the Atlanteans were allergic to the element Xenon on Earth's air. To solve the problem, Brainiac 5 suggested that artificial evolution could change the Vruunians into underwater-dwelling Atlanteans, with fish tails. This was agreed, and so the Atlanteans became the ancestors of Lori Lemaris and her fellows.