4 books in series

Star Wars Rebels: Servants of the Empire

Star Wars Rebels: Servants of the Empire is a 4-book series with 4 released primary works first released in 2014 with contributions by Jason Fry.

Servants of the Empire: Edge of the Galaxy
Servants of the Empire: Rebel in the Ranks
Servants of the Empire: Imperial Justice
Servants of the Empire: The Secret Academy