Origin of Pietas Sci-Fi - An Immortal King, a Mortal Enemy, and a Quest

The immortal king Pietas is exiled on a planet with no one but Six, the human who guarded him during a year of transport. Pietas's ordeal transformed him from immortal superman to a man who cannot even feed himself. Like Mandela and his guard, Pietas and Six come to respect one another. Once on the planet, Six is the key to Pietas's survival. It's the two of them, and only them. If the human deserts him, Pietas will die, permanently. That doesn't mean he'll humiliate himself by asking for help. Until he realizes he will never find his people without it. Now, saving his people means depending on the one thing Pietas swore did not exist -- the honor of a human...