Here is the full list of all 44 Champions of Anteria achievements.
Conquer 1 territory
Unlock 1 sector of the kingdom map
Finish the tutorial adventure
Start a game
Conquer 5 territories
Conquer 10 territories
Unlock 4 sectors of the kingdom map
Unlock all sectors of the kingdom map
Conquer 1 enemy territory
Conquer 5 enemy territories
Conquer 10 enemy territories
Conquer 1 territory belonging to the Frostbeards
Conquer 3 territories belonging to the Frostbeards
Conquer 1 territory belonging to the Dune Tribe
Conquer 3 territories belonging to the Dune Tribe
Conquer 1 territory belonging to the Broken Crown
Conquer 3 territories belonging to the Broken Crown
Conquer 1 territory belonging to the Dark Cult
Conquer 3 territories belonging to the Dark Cult
Repel 1 enemy attack in a defense scenario
Repel 5 enemy attacks in a defense scenario
Repel 10 enemy attacks in a defense scenario
Build 1 trading post
Build 5 trading posts
Build 10 trading posts
Build 20 trading posts
Build 1 fortification
Build 5 fortifications
Build 10 fortifications
Build 20 fortifications
Defeat the Frostbeards
Defeat the Dune Tribe
Defeat the Broken Crown
Defeat the Dark Cult
Conquer all map territories
Win the game in under 40 turns
Win the game without losing a territory
Win the game without losing a single adventure
Beat the game in Ironman Mode
Beat the game in Ironman Mode in under 40 turns
Win the game in Ironman Mode without losing a territory
Win the game in Ironman Mode while owning all territories
Beat the game in Ironman Mode without losing a single adventure
Win the game without any Champion dying