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