The Guardians Add-on for Endless Legend - Emperor Edition has 8 achievements.
Capture a city containing a Legendary Building.
Have the 5 different Guardians at the same time.
Contribute to a completed Co-operative Quest.
Kill a Guardian.
...in the ruins all across Auriga, and even throughout...
Win a game with generation presets other than default.
Have the 5 Legendary Buildings at the same time.
Complete all the Legendary Deeds, across any number of playthroughs.