Full list of all 60 Diplomacy is Not an Option achievements.
The base game contains 53 achievements, and there is 1 DLC pack containing 7 achievements.
Complete the story campaign the most civilized way
Side with the Undead
Twilight Overlord's Avatar resurrected 20+ zombies at once
Twilight Overlord's Avatar resurrected 50+ zombies at once
Twilight Overlord's Avatar resurrected 100+ zombies at once
Complete the "Dangerous tour" mission in 40 days
Take Abberlore without using Grim Pilgrims or Nightmare Generals