Here is the full list of all 23 The Heroines' Last Anthem achievements.
Maxed-out Ialantha's skill levels
Performed 10 Glory Charges
Maxed-out Rela's skill levels
Defeated the Azure Demon Lord
Unlocked a hidden story
Maxed-out Ewella's skill levels
Collected all heroic spirits
Fired 100 throwing knives
Collected 3000 gold
Defeated Chuq
Fired 100 arrows
Defeated Dhiwoubos
Destroyed the ancient evil orb
Defeated an orc heavy-armored warrior
Jumped 10 times on a mushroom
Opened a door with a key
Opened 10 treasure chests
Upgraded a skill level
Colleged 300 Gold
Completed the tutorial
Found a heroic spirit in a hidden area
Defeated all bosses in Hard Mode
Defeated 50 orcs