Jarzen Tadel - Echoes of Destiny by Robert Jacobi

Jarzen awakens aboard a crashed space ship; with no memory of who he is; or of what he is capable of doing. Jarzen is among four perfect specimens who are obviously from a different race; as they are all more than a galactic foot taller than Jarzen and twice his mass in stature. Together, they set out on foot in a primitive world where bows, arrows, spears, swords, and hatchets are the weapons of the era.