Here is the full list of all 50 Alder Forge achievements.
Defeat Prolepsis Boss 1
Defeat Prolepsis Boss 2
Acquire the Crimson witch Anima Stone in the Prolepsis and use the Crimson Bells Skill in battle
Read your first book
Finish your first activity
Defeat Chapter 1 Boss 1
Defeat Chapter 1 Boss 2
Defeat Chapter 1 Mini-Boss 2 and acquire the Silvis Anima Stone
Defeat Chapter 1 Boss 3
Defeat Chapter 1 Boss 4
Defeat Chapter 1 Boss 5
Visit your chambers in the Pax Residence in the Prologue
Inspect the continent map in the Atlas Court
Win 100 battle
Speak to Duke Clement De Roy in Schwarden Village
Speak to Ronya La Roue in Lion's Gate Military Base
Craft 100 item/equipment
Speak to the stray cat in the Sanctuary of Crius in the Prolepsis
Survive and Bypass the Oven Corridor
Speak to Ryo in the Atlas Court
Defeat Chapter 2 Boss 1
Defeat Chapter 2 Boss 4
Defeat Chapter 2 Boss 5
Defeat Chapter 2 Boss 6
Defeat Chapter 2 Boss 7
Defeat Chapter 2 Boss 8
Win 500 battle
Craft 500 item/equipment
Survive the Sect of Tartarus' traps.
Win 1000 battle
Defeat Chapter 3 Boss 1
Defeat Chapter 3 Boss 2
Defeat Chapter 3 Boss 3
Defeat Chapter 3 Boss 4
Defeat Chapter 3 Boss 5
Defeat Chapter 3 Boss 8
Conclude the Battle of Voxenhold
Defeat Chapter 3 Boss 9
Check on Edna Raysark after the battle of Voxenhold
Acquire the Dragon Core Anima Stone in Val Réal City at night.
Defeat Chapter 4 Boss 1
Acquire Prometheus.
Win the second Holy Battle
Win the final Holy Battle
Defeat Chapter 4 Boss 4
Defeat the Game's Final Bosses