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