Adapted into the first volume of the Seikai Trilogy manga

Planet Martine is suddenly attacked! The alien invaders are known as the Abh. They are of human origin, but have been genetically modified so that each Abh has superior talent, skill, beauty, and longevity. Martine's president surrenders completely in the face of the Abh's awesome military power. Through a bizarre twist of fate, his son Jinto becomes a nobleman in the Abh's vast, intergalactic empire.

From Tokyopop:
After his home world is ruthlessly taken over by the Abh - a space-faring race that has conquered thousands of galaxies - a boy named Jinto begins an unforgettable journey that stretches the boundaries of the final frontier. With a beautiful princess at his side, he will attempt to unlock the secret behind the Abh domination and discover that all's fair in love and interplanetary war.