Shadow Hunter — a series by QM

Darras was a veteran of a brutal five year war against a despicable yet powerful enemy. Ordered to hold for three days as the last of his defeated nation’s people were loaded onto colonisation ships, he’d done the impossible and held for ten, leaving the invaders with nothing but an empty port and massive casualties. He then discovered that death was not to be his, with a new life and a new challenge with the blessings of a goddess who needed his help. / (Reviews)

Darras, a man out of place and time, serves his goddess in an eternal war with her brother, who wants nothing more than a society dominated by might makes right.