Fragments of a Chain - The Drath Series, #4

Mohana stumbled, head screaming with pain in the blinding sunlight as shouts echoed around him. His memory wiped, battle raged around him. Mohana had no idea which side he was on. But one side wanted him dead while the other, especially Tiyamike, risked her life to keep him alive. Finding his memory meant certain execution. Not finding it might mean the downfall of galactic civilization.