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