Here is the full list of all 40 Sorcerer King achievements.
Complete the Campaign
Win as the Commander
Slay Aegethon
Destroy one of the Sorcerer King's Strongholds
Complete a Champion Quest to recruit a new Champion to your cause
Defeat a Minor Faction that has sided with the Sorcerer King
Play for 5 hours
Slay Vetrar
Reach level 15 with a champion
Equip a champion with items in every slot
Win a "predicted defeat" tactical battle without taking damage
Win a "predicted defeat" tactical battle
Use pioneers to upgrade an Outpost
Ally with a Minor Faction
Use a pioneer to build an Outpost
Get a city to level 9
Use the Sovereign's magic to intervene in a tactical battle
Claim a Shard
Settle a new city
Get a city to level 5
Reach level 5 with a champion
Craft an item
Lower the Doomsday Counter
Win a tactical battle
Build your first city improvement
Channel the focus of your Magic between Mana, Lore, and Sovereign Skill
Complete a Quest
Play for 15 hours
Play for 40 hours
Play for 100 hours
Found 5 additional cities in a single game
Kill an enemy with a pioneer attack
Win 20 "predicted defeat" tactical battles without taking damage
Win a game on Insane Difficulty
Win a game without a single shard destroyed
Win as the Guardian
Win as the Tyrant
Win as the Wizard
Win as the Priest
Win as the Tinkerer