Here is the full list of all 19 Winged Sakura: Demon Civil War achievements.
Save Nixi
Formed a contract with Lily
Advanced to the second floor
Completed the Prologue
Unlocked all other Achievements
Successfully escorted the new Incarnate
Find the medicine and save the Rebellion Leader
Successfully defended the Rebellions from the Pandemoniums
Successfully invaded Pandemonium
Successfully conquered Pandemonium
Defeat the Werewolf in Pandemonium
Defeat the Snake Queen in Pandemonium
Defeat the traitor in Pandemonium
Defeat the Elf Guardian in the Tower of Incarnation
Defeat the Fire Guardian in the Tower of Incarnation
Defeat the Demon God in the Tower of Incarnation
Level 99 on 5 or more characters.
Beat the game and discovered the truth behind the Demon Civil War
Advanced to the eleventh floor