Legends of the Alliance is a companion app for the Star Wars: Imperial Assault board game, a scenario-based game of tactical combat. When you play with Legends of the Alliance, the app assumes the role of the Imperials, while you and your friends form a team of Rebel heroes fighting to bring down the Galactic Empire.
Legends of the Alliance introduces a completely cooperative way to play Imperial Assault, freeing you and your friends to work together to overcome challenges set before you by the evil Empire. With a full campaign featuring exciting new missions and the ability to incorporate your entire collection of physical Imperial Assault products, Legends of the Alliance provides a thrilling new way to experience Imperial Assault!
Source: The Developer Website.