Here is the full list of all 36 Royal Merchant achievements.
Dont be a Batman - do it!
Kill 50 enemies
Kill 300 enemies
Kill over 9000 enemies
Establish a Castle
Find Dwarf Mine
Form a holy party
Form a dark party
Form a dwarf party
Hire first Hero
Hire 3 Heroes
Hire 10 Heroes
Level up any Hero 5 times
Level up any Hero 10 times
Level up any Hero 20 times
Reach 1 level of training
Reach 5 level of training
Reach 10 level of training
Reach 20 level of training
Sacrifice a Ram
Sacrifice a Sheep
Sacrifice a Rabbit
Sacrifice a Fox
Craft item level 1
Craft item level 2
Craft item level 3
Craft item level 4
Get item quality 2
Get item quality 3
Get item quality 4
Get item quality 5
Fully equip a Hero
Finish Act 1: Undeads Swamps
Finish Act 2: Greenscins Hills
Finish Act 3: Egypt Plains
Finish Act 4: Fantasy Mountains