Here is the full list of all 27 Masquerada: Songs and Shadows achievements.
Defeat the Ancient Feravaro.
Defeat the Matron.
Respec once.
Defeat the Saltbreather.
Defeat the Antiquarian.
Defeat the Triplets.
Fully upgrade a skill.
Defeat the Greater Bolgia.
Complete the Prologue
Defeat the Chimera.
Defeat the Mangiatore.
Defeat the Ridiro Queen.
Win the duel.
Defeat the Brehon.
Clear the final battle.
Watch the Epilogue.
Collect all inks and runes.
Collect all the codices.
Practice in the Training Grounds.
Revisit a scene.
Listen to all of Kalden's optional dialogues.
Listen to all of Amadea's optional dialogues.
Listen to all of Tiziana's optional dialogues.
Listen to all of Vasco's optional dialogues.
Listen to all of Leventhos' optional dialogues.
Activate 100 Mask abilities.
Trigger 250 Elemental Tags.