The head of administration of Industria, Lepka technically serves under the Industria High Council, a group of scientists. However, over the course of the series, he becomes the sole dictator of Industria, and the primary antagonist. Lepka desires to extract the secret of solar power from Lao to power his weapons, allowing him to rule over what remains of the world.
Actually, Lepka is a descendant of Colonel Muska in "Castle in the Sky".