Board Thread:General Discussion/@comment-31658135-20191022102616/@comment-75.100.64.94-20191022111723

Howard says:

When you reach 100% Magister at 1 location, you get the first Star of the Ace of Aces achievement. At 5 locations you get the second Star. At 10 locations, the get the third star. The Ace of Aces is found at the very bottom of the achievements list. The rewards are underwhelming.