Here is the full list of all 51 Disgaea 4: A Promise Unforgotten trophies - there are 42 bronze, 5 silver, 3 gold and 1 platinum.
Conduct your first Map Edit.
Defeat Pringer X: Roar in the Land of Carnage.
Increase an item up to LV 300.
Visit the Land of Carnage.
Enforce discipline 100 times.
Accidentally destroy Axel's statue in the Mystery Room.
Open 100 treasure chests.
Defeat Zetta in the Post-Game and make him an ally.
Steal 10 Rare and/or Legendary items.
Persuade by force three times. Demons should always resort to violence!
Defeat Asagi in the Post-Game and make her an ally.
Defeat Laharl in the Post-Game and make him an ally.
Defeat Etna in the Post-Game and make her an ally.
Defeat Raspberyl in the Post-Game and make her an ally.
Defeat Archangel Flonne in the Post-Game and make her an ally.
Defeat Axel in the Post-Game and make him an ally.
Train an ally up to LV 9999.
Open all chests at the base from Episode 1 to Post-Game.
Conduct your first Reverse Pirating.
Get over 100,000,000 HL.
Inflict 100,000 damage.
Clear 30 floors in the Item World.
Clear the main game and unlock the Post-Game.
Watch Fenrich's epilogue.
Reincarnate for the first time.
Max out the Rosen Queen Company customer level.
Clear up to Episode 7 in the main story.
Cancel 1,000 battle actions.
Get a Game Over from having your party get defeated.
Throw and capture an enemy character in the base panel.
Defeat an ally character.
Clear up to Episode 3 in the main story.
Watch the opening anime. Enjoy Disgaea 4!
Complete all other trophies. You have obtained all the trophies.
Inflict 10,000,000,000 damage.
Unlock all Evil Symbols.
Collect all items (excluding grades). Now aim for completing all the grades, too!
Collect all of the Pirate Ship parts.
All ranks of all job and monster classes can be created through Character Creation.
Watch all of the special skills.
Clear all of the X-Dimension maps.
Watch Fuka's epilogue.
Watch Desco's epilogue.
Watch Emizel's epilogue.
Watch Artina's epilogue.
Defeat God (self-proclaimed) and watch the ending.
Defeat Prinny Kurtis in the Post-Game and make him an ally.
Fight five battles with the "Classic" display option. Pixels still rock!
Explode ten Prinnies in a row.
Give 50 bribes.
Defeat 100 Pirate Crew members in the Item World.