Here is the full list of all 30 Arietta of Spirits achievements.
Find all lost Spirit Cubs.
Pick blueberries for Mom.
Find all of Midri's goods.
Find Grandma's portrait.
Complete the game.
Escape from the Sunken Realm.
Defeat the Sunken Behemoth.
Help Minerva cross over to the afterlife.
Harvest all vegetables from the garden.
Complete the Journal.
Defeat the Roamer Behemoth.
Unlock the Large Roamer Core.
Ladders finally fixed.
Unlock the Medium Roamer Core.
Defeat the Cloaked Roamer.
Find Gibb's workshop.
Defeat the Spikeroot Roamer.
Obtain the Herbicide.
Unlock the Spirit Shield.
Unlock the Small Roamer Core.
Find Minerva's hut.
Help out Father in a sticky situation.
Get to keep Grandma's Silver Ring.
Defeat the Huge Roamer.
Obtain the Spirit Sword.
Become a Bound.
Defeat the Wasp Queen.
Kill a butterfly.
Obtain the Wooden Sword.
Complete the game on Extreme Mode.