The The Masters of Evil Character & Level Pack Add-on for LEGO Marvel's Avengers has 5 achievements worth 50 gamerscore.
Defeat 20 enemies as the Black Knight (Dane Whitman) during Free Play
Set both Free Play characters as the Enchantress and Executioner in the Asgard hub area
Complete the 'The Masters of Evil' level with all Minikits unlocked
Complete the 'The Masters of Evil' level
Complete the 'The Masters of Evil' level after achieving True Avenger status