This expansion for Hidden Leaders comes with 3 new modules:

A new faction, four leaders, and 20 new heroes. The guardians are a powerful race that everyone can use but using them too much will lead to the Guardian Leaders winning.

Artifacts will upgrade your leader character. Each artifact gives the respective player a unique ability that can be used 2-3 times during the game. 

A bag full of nasty corruption tokens. Two times during the game, a wave of corruption allows you to secretly change the alliance of your heroes or the heroes of your friends. But be careful: some of these changes are dangerous traps that players can use to protect their heroes.