Path of the Eclipse is a novel written by Chelsea Quinn Yarbro. It was first published in 1981 and is the fourth book in the Saint-Germain book series.
Description[]
There is trouble in 13th century China. A wind blows from the west and has a name--Jenghiz Khan. Pledged to help a beautiful woman warrior, St. Germain has a terrible secret--he has the power to bestow death or eternal life as a vampire.