Here is the full list of all 12 RAW Realms of Ancient War achievements.
Finish the game with all heroes
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
Collect 50,000 gold coins
Start a cooperative game
Equip epic or legendary armor
Kill 1000 mobs in the campaign
Complete a level without dying