King Kayos served as the father of Princess Leia and held the position of ruler over the planet Aquilae. Biggs and Windy were his two sons, making them Leia's brothers. In a treacherous act, Kayos met his death at the hands of the New Galactic Empire while he was on his way to the Aquilaean Senate to discuss a proposed treaty; subsequently, the Senate surrendered.
Queen Breha was his spouse. She gave General Luke Skywalker the order to bring Leia to Ophuchi so that she could get assistance from the Chrome Companies and put her daughter on the throne. Given that Leia's younger brothers were further down the line of succession, it is clear that the Aquilaeans adhered to a rigid system of primogeniture.
Kayos appeared within the initial script of the original movie. The name of his wife was later used in Episode III for Leia's adoptive mother residing on Alderaan. However, Prince Bail Organa eventually took Kayos' place.