Here is the full list of all 29 Decay of Logos achievements.
Unlock all the achievements.
Play your role as a pawn in Master Yaal's revenge plot.
Open all the chests.
Turn your back on Master Yaal, leaving him to his fate.
Execute Master Yaal.
Defeat Master Yaal.
Survive the battle against King Telos until the very end.
Collect all the pieces of King's Guard armor set.
Pick up one of each Mask type worn by the Masked Youths of the Wadi.
Lose the battle against King Telos.
Collect all the memory ripples contained in the Echo Shells.
Release the Masked Boy from the cage and exhaust all his dialogue lines.
Knock on Nediva's door in the Bosk of Silens and exhaust all her dialogue lines.
Defeat the Slug behemoth.
Free Eitan and exhaust all his dialogue lines.
Defeat the Chomper behemoth.
Release the trapped youths after defeating Prince Kairos and Mother Reba.
Defeat Prince Kairos and Mother Reba.
Meet Yoran and exhaust all his dialogue lines.
Defeat all the remaining Ancestral Brutes.
Defeat the imprisoned Ancestral War Chief.
Read all the Ancestral rune stones.
Learn all the Magicae Twines taught by the young Magus.
Defeat Prince Ethos.
Defeat one of the Royal Elite Soldiers of the Realm.
Find Nuri in the Hamlet and exhaust all her dialogue lines.
Defeat Prince Pathos.
Defeat the vengeful Ancestral Brute in Palus, the last of the lumberjack twins.
Defeat the axe-wielding Ancestral Brute in Laetus Grove, one of the lumberjack twins.