The Suns of Scorpio by Alan Burt Akers

Slave of the colossus builders or scourge of the Inland Sea? Both roles await Dray Prescot on his return to Kregen. Torn between two contending forces, the Star Lords and the Savanti, Prescot himself wants only to find his beloved, the Princess Delia of the Blue Mountains. But the powers that had drawn him across interstellar space to the world that orbit the red and green suns in the Constellation Scorpio have set him a task, the nature of which even he cannot fully comprehend...

Dray Prescot's saga has been aclaimed as the best planetary adventure series since Burroughs stopped writing about Barsoom.

The Suns of Scorpio is the second book in the epic saga of Dray Prescot of Earth and of Kregen.