Here is the full list of all 49 Utawarerumono: Prelude to the Fallen achievements.
Dealt 300+ damage to a single enemy.
Completed Battle to the Death on the Bridge.
Completed Evenkurugan Woman.
Completed Special Attack.
Completed Blocking the Shikeripechim Invasion.
Tried training.
Completed Decisive Battle.
Completed Imperial Capital Invasion.
Completed Nuwangi.
Completed Tatokori Gate.
Used a final strike.
Completed Daughter of the Forest.
Used a co-op chain.
Completed Path of No Return.
Completed Revolt.
Completed Ruler of the Wild Forest.
Completed Uninvited Guests.
Successfully performed a chain attack.
Obtained all achievements.
Completed False Truths - Part 2.
Completed Giriyaginan Gladiator.
Completed Infiltration.
Completed Karulawaturei.
Completed Pursuit.
Completed Princess of a Fallen Empire.
Completed Abandoned Feelings.
Completed The Daybreakers.
Completed Hansana Offense & Defense.
Completed Hunter & Hunted - Part 2.
Completed Abh-kamu.
Completed Burning Prison.
Completed The Fallen.
Completed Mask.
Completed Kuuya.
Completed Primordial Dream - Part 2.
Completed Demander of Power.
Completed Great Seal - Part 2.
Reached the ending.
Completed Where the Wild Things March.
Used every main character's final strike.
Used every main character's co-op chain.
Dealt 750+ damage to a single enemy.
Dealt 1,800+ damage to a single enemy.
Tried a free battle.
Completed all training battles.
Acquired all rewards from training.
Completely filled out the encyclopedia.
Viewed all event scenes.
Listened to every BGM.