01 - Warrior of Two Worlds by Manly Wade Wellman

He is a hero from two planets, thrust through the vastness of space to defend a nation against merciless invaders. Meet Yandro, the Stranger of the Prophecy, who discovers he must battle on both sides of a cosmic conflict. Dive into this thrilling swashbuckler in space by Manly Wade Wellman—an adventure you wont want to miss! - Summary by the publisher and Phil Chenevert