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