Here is the full list of all 51 Disgaea 3: Absence of Justice (EU) trophies - there are 42 bronze, 5 silver, 3 gold and 1 platinum.
Get all other trophies.
Steal from all the Innocents and treasure boxes while Reverse Pirating.
Steal from all the Innocents while Reverse Pirating.
Get all the Reverse Pirating treasure boxes.
Counter Attack over 10 times.
Do over 10,000,000,000 damage.
Clear Geo Blocks with 10 color changes in a row.
Receive 9 times and move over 60 panels.
Receive 4 times and move over 20 panels.
Magichange 5 times in a battle.
Accomplish over 255 combos in battle.
Defeat an enemy with 10 combos or more.
Defeat an enemy with a 10 story tower.
Defeat the 10 Gents Pirates in the Item World.
Find Axel in the Item World.
Get a Trophy from a Trophy Shop on the 90th floor.
Defeat the Prinny Pirates in the Item World.
Defeat the UFO Pirates(?) in the Item World.
Defeat the Baal Pirates in the Item World.
Defeat the Horizon Pirates in the Item World.
Beat floors 1 to 100 in a Land of Carnage Item World without exiting.
Do over 100,000,000 damage.
Capture an enemy during battle.
Defeat the Red Pirates in the Item World.
Defeat the Shinsengumi in the Item World.
Defeat the Boney Pirates in the Item World.
Defeat the Garden Pirates in the Item World.
Play for over 10 hours without stopping.
Defeat the Kit Cat Pirates in the Item World.
Defeat the Element Pirates in the Item World.
Defeat Z Pirates in the Item World.
Defeat the Pirate Club in the Item World.
Defeat the Ghost Pirates in the Item World.
Defeat Wise Innocents in the Item World.
Defeat the Pirate Cleaners in the Item World.
Defeat Eryngi Pirates in the Item World.
Defeat the Cheerates in the Item World.
Defeat the Asian Pirates in the Item World.
Defeat UFO? in the Item World.
Do over 1,000,000 damage.
Beat floors 1 to 100 in an Item World without exiting.
Defeat the Cowboy Pirates in the Item World.
Defeat the Sports Pirates in the Item World.
Defeat Lucky Pirates in the Item World.
Talk to the Cat God at the top of the Treasure Tower.
Defeat Donnax2 Pirates in the Item World.
Clear Geo Panels with 5 color changes in a row.
Get all the treasure boxes in the Treasure Room in the Item World.
Force the Student Council to approve your Home Room request.
Get hit by ABC Gum.
Jump inside Evil Academy 100 times.