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