Here is the full list of all 53 The Legend of Heroes: Trails of Cold Steel IV achievements.
Reached the true ending.
Completed the finale.
Acquired over a million mira.
Completed all quests.
Gathered all 5 lost arts quartz.
Opened every trial chest.
Achieved a Unity Grade of Unbreakable.
Took all landscape photos and reported them to Rex.
Completely filled the fishing section in the notebook. (All 30 types of fish + Rod Lv. Max)
Completely filled the books section in the notebook.
Completely filled the recipe section in the notebook.
Achieved a Special Ops rank of A0.
Raised a master quartz to level 10.
Spent the evening before the final battle with Musse.
Spent the evening before the final battle with Emma.
Spent the evening before the final battle with Fie.
Spent the evening before the final battle with Sara.
Spent the evening before the final battle with Alfin.
Spent the evening before the final battle with Elise.
Completed Eventide.
Forged a strong bond with Kurt, Ash, Elliot, Machias, Jusis, Gaius, and Crow.
Completed Act 3.
Raised any two characters to Link Level 7.
Won 700 battles.
Completed Act 2.
Used over 500 follow-up attacks in battle.
Initiated 300 advantage encounters. (Including double and triple advantage)
Inflicted Break over 800 times.
Used 100 S-Crafts in battle.
Won a battle with a tactical bonus of x3.0 or greater.
Used Burst in battle 50 times.
Completed Fragments.
Completed Act 1.
Used Rush in battle 100 times.
Earned an S-Rank on any act.
Won 100 battles.
Completed the prologue.
Infiltrated Orchis Tower.
Mastered Trails of Cold Steel IV and earned every achievement.
Completed the game on nightmare difficulty.
Opened every treasure chest.
Completely filled the battle section in the notebook. (Besides the Extra category)
Completely filled the character section in the notebook.
Completely filled the cards section in the notebook.
Won against all opponents in Pom! Pom! Party!
Gathered all 31 varieties of master quartz.
Used Brave Order in battle over 100 times.
Spent the evening before the final battle with Juna.
Spent the evening before the final battle with Altina.
Spent the evening before the final battle with Alisa.
Spent the evening before the final battle with Laura.
Spent the evening before the final battle with Towa.
Forged a strong bond with Celine and Duvalie.