Here is the full list of all 49 Nights of Azure achievements.
Viewed an extra ending.
Summoned Servans 1000 times.
Defeated Christophorus.
Arnice achieved her max level.
Gave 1000 orders to Servans.
Arnice equipped Hamelin's Pipe and cleared a battle.
Arnice equipped Glass Blade and cleared a battle.
Achieved 500-Chain.
Actualized 40 Servans.
Executed trades all over the world.
Defeated Mistral.
Collected all Servans.
Transformed into Nightmare form.
Viewed an ending.
Defeated Ludegert.
Transformed into Armor form.
Maxed out a Servan's level.
Defeated Corrine.
Completed 100 tasks.
Defeated Blueblood Dragon Mavelus.
Executed trades in half of the world.
Collected 50% of items.
Transformed into Phantom form.
Transformed into Rabbit form.
Defeated Blueblood Maiden Milaya.
Collected 50% of Servans.
Defeated Blueblood Count Rosier.
Executed a trade for the first time.
Summoned a Servan 100 times.
Defeated Blueblood Cavalry Carousel.
Defeated 1,000 enemies.
Gave 100 orders to Servans.
Achieved 300-Chain.
Cleared first Arena task.
Completed first task.
Defeated Blueblood Dragon.
Achieved 100-Chain.
Transformed into Demon form.
Actualized a Servan for the first time.
Defeated 100 enemies.
Gave an order to a Servan for the first time.
Summoned a Servan for the first time.
Collected all achievements.
Actualized 80 Servans.
Completed 300 tasks.
Cleared half of Arena tasks.
Cleared all Arena tasks.
Collected all items.
Defeated 10,000 enemies.