Here is the full list of all 86 AETHERIS achievements.
Win a fight against the Hauger without any Spirit assigned
Reach the Flying cities
Defeat the Mother of Darkness
Reach at least 50 Strength with one of your Vazzards
Win a fight against Claymort
Win a fight against a Pilgrim
Win a fight against an Excavator
Deal at least 150 damage in a single strike
Win a fight against a Pirate
Reach the last chapter of the game
Win a fight against the Gulp-Gulp King
Win a fight after destroying the Sentinel
Get more Spirits than living Vazzards in your village
Win a fight against a Moolten without any Spirit assigned
Win a fight against a Flayard without any Spirit assigned
Reach at least 15 SP with one of your Vazzards
Win a fight against a Gulp-Gulp
Win a fight against the Bilgoat
Reach the sixth chapter of the game
Win a fight against the Hauger
Reach 100% Critical Hit Chances with one of your Vazzards
Win a fight against a Nosey
Reach the fifth chapter of the game
Win a fight against a Myriapace
Win a fight against Pau'Ju
Win a fight against an Arboreal
Walk into one of your own trap
Play a very empathetic Vazzard
Reach 100% Dodge with one of your Vazzards
Win a fight against Marley
Win a fight against a Larvenom
Reach the fourth chapter of the game
Win a fight against an Hawtorn
Win a fight against an Oakraged
Reach at least 50 Power with one of your Vazzards
Win a fight against a Lepracorn
Reach the third chapter of the game
Play a very spiritual Vazzard
Play a very brutal Vazzard
Win a fight against Elioch
Win a fight against a Skortick
Lose your whole team
Play a very rational Vazzard
Win a fight against the Anomaly
Win a fight after losing one of your Vazzards for good
Win a fight against a Shadgnaw
Win a fight against a Jackcrow
Win a fight against a Croakook
Reach the second chapter of the game
Win a fight against a Moolten
Win a fight alongside Lua'Nu
Win a fight against a Flayhound
Win a fight against a Flayard
Complete the tutorial
Reach the first chapter of the game
Win a fight against an Augur
Win a fight against an Augur without any Spirit assigned
Win a fight against an Arboreal without any Spirit assigned
Win a fight against Claymort without any Spirit assigned
Win a fight against the Eye
Win a fight alongside Moal
Win a fight against a Slave
Win a fight against a Slave without any Spirit assigned
Win a fight agaisnt a brawler
Use the skill of a Vazzard chief
Reach at least 300 HP with one of your Vazzards
Rest in the camp when at least two Vazzards have less than 10 HP
Win a fight in 2 rounds or less
Win a fight with a Vazzard having 5 HP or less
Win a fight against Elioch without any Spirit assigned
Win a fight where you spent at least 8 SP in a single turn
Win a fight after killing one of your allies
Win a fight after performing at least 5 critical strikes with guns and rifles
Win a fight where you used at least 3 healing skills in a single turn
Win a fight after killing at least 6 enemies with a single Vazzard
Win a fight without having been in contact with a single enemy
Win a fight after dealing more than 1000 damage with a single Vazzard
Win a fight without moving
Win a fight against the Gulp-Gulp King without any Spirit assigned
Reach at least 500 Critical Damage with one of your Vazzards
Use at least 5 differents skills in a single turn
Play an empathetic brutal mystically rational Vazzard