Here is the full list of all 53 The Legend of Heroes: Sen no Kiseki IV -THE END OF SAGA- achievements.
Earned all achievements.
Completed the game on nightmare difficulty.
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 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 Musse.
Spent the evening before the final battle with Altina.
Spent the evening before the final battle with Juna.
Forged a strong bond with Kurt, Ash, Elliot, Machias, Jusis, Gaius, and Crow.
Completely filled the character section in the notebook.
Reached the true ending.
Completely filled the battle section in the notebook. (Besides the Extra category)
Completed the finale.
Opened every treasure chest.
Acquired over a million mira.
Achieved a Unity Grade of Unbreakable.
Completely filled the recipe section in the notebook.
Completed all quests.
Gathered all 5 lost arts quartz.
Opened every trial chest.
Completely filled the fishing section in the notebook. (All 30 types of fish + Rod Lv. Max)
Took all landscape photos and reported them to Rex.
Gathered all 31 varieties of master quartz.
Achieved a Special Ops rank of A0.
Completely filled the books section in the notebook.
Raised any two characters to Link Level 7.
Won against all opponents in Pom! Pom! Party!
Completely filled the cards section in the notebook.
Spent the evening before the final battle with Towa.
Completed Eventide.
Spent the evening before the final battle with Elise.
Forged a strong bond with Celine and Duvalie.
Completed Act 3.
Raised a master quartz to level 10.
Won 700 battles.
Completed Act 2.
Inflicted Break over 800 times.
Completed Fragments.
Initiated 300 advantage encounters. (Including double and triple advantage)
Used Brave Order in battle over 100 times.
Used 100 S-Crafts in battle.
Completed Act 1.
Used over 500 follow-up attacks in battle.
Used Rush in battle 100 times.
Used Burst in battle 50 times.
Earned an S-Rank on any act.
Won 100 battles.
Won a battle with a tactical bonus of x3.0 or greater.
Completed the prologue.
Infiltrated Orchis Tower.