Commander Varvatos Vex is a main character of 3 Below.
Vex used to live on a distant planet called Akiridion-5 with the royal family, as well as the commander of this planet. When the planet got taken over by some evil dictator, Vex became Princess Aja and Prince Krel's guardian when they fled the planet. They landed on Earth and settled into the town of Arcadia. There disguised themselves as a human family.