Inspector of the Cross Series by John B. Rosenman

Thanks to suspended animation, Turtan is over 3500 years old and travels on freeze ships to distant worlds. His mission is to investigate weapons to help humanity turn the tide against their ancient nemesis…the Cenknife. Vicious aliens, the Cenknife seek to conquer the universe and enslave humanity.When Turtan discovers just such a weapon, a beautiful, seductive woman stands in his way. He must use all his skills, abilities, and courage to meet the crisis and save untold billions of lives.