The Ivory Star

Eric Corbin, a deep space explorer, finds himself marooned on an unknown planet, along with his friend Angus MacTavish.
The planet is home to medieval human society, four countries played against each other by the thousand-year-old sorcerer named Uhr. Taken prisoner, Eric and Angus soon discover that they are pawns in a thousand-year-old struggle.
Surrounded by the mysterious Eagle Knights, the deadly Red Priests, and the rebellious Lord Valerion, Eric and Angus have no idea whom to trust. And all, it seems, are pawns in Uhr's deadly game.