Here is the full list of all 12 Heroes Legends: Conquerors of Kolhar achievements.
You finished the story missions
Defeat Jahen in Story
You reached level 60 with one of your adventurers.
Jomon has joined your party
Defeat the Grenk Warlord in Story
Defeat Sijsen in Story
You reached level 15 with one of your adventurers.
You equipped your first Special Move
Tysha has joined your party
You crafted your first piece of armor
You crafted your first item
You finished the challenge missions