Here is the full list of all 12 RAW Realms of Ancient War achievements.
Hit an enemy for 2500 HP damage
Complete the game with any hero
Raise all of your skills to level 1
Find 5 statues of Kilthi
Possess 15 mobs
Complete 50 quests
Equip epic or legendary armor
Collect 50,000 gold coins
Kill 1000 mobs in the campaign
Complete a level without dying
Start a cooperative game
Finish the game with all heroes