Here is the full list of all 19 Symphony of War: The Nephilim Saga achievements.
Rescue all 4 children in Chapter 15.
Defeat all enemies in Chapter 12.
Defeat Beatrix in Chapter 11.
Complete the main story on Captain difficulty.
Unlock all Techs in a single playthrough.
Reach Max Faction Rank.
Surrender all the Imperial Squads in Chapter 27.
Have 9 Units in one Squad.
Surrender 200 enemy Units in a single playthrough.
Form a Bond relationship.
Reach Faction Rank 9.
Use a Proof of Merit on a Unit.
Hire a Unique Mercenary.
Class change to Tier 3.
Find or purchase an Artifact of Legendary rarity.
Reach Faction Rank 4.
Class change to Tier 2.
Army size reaches 150 Units.
Complete the main story on Warlord difficulty.