Disgaea 3: Absence of Detention Cheats

Demon King: Have It Your Way (Bronze): Force your will on them, like the demon your are!
Eryngi Baal Slayer (Bronze): I'm not going to get my "a" back?
Finale Complete (Bronze): I will...become the Overlord!
Finger Flicking Good (Bronze): Mooove! My fingers are on fire!!!
First Setback (Bronze): That was just a warm. Now I'm ready to go!
Giga Damage! (Bronze): More training! You can do more!
Gotcha! (Bronze): Yay! You got a new ally!
Hardcore Gamer! (Bronze): Thanks for playing! But we suggest you take a break.
Hop, Step, Jump (Bronze): Isn't jumping sooo much fun?
I Got Gummed... (Bronze): Why me...?
I Had an Axeldent! (Bronze): Axel never stops working! Even in the Item World!
It's Da Bomb! (Bronze): Playing with bombs in Homeroom? You're quite an honor student.
Item Spelunker (Bronze): Congratulations on reaching the 100th floor! You're on the right track to become a hardcore player!
IWCA Flyweight Champion (Bronze): You are the Item World Champ!
Kneel Before Cat God! (Bronze): *blush* Oh, you can stand, meow.
Magichangician (Bronze): Transform! Yeah!
Majin Academy Complete (Bronze): I shall take over this Academy!
Master of the Chain (Bronze): Do massive chains! Use your brain to the max!
Mega Damage! (Bronze): You gotta train! For starters, a million damage!
Omni Bonus! (Bronze): It's only natural for a demon to take everything.
PE Teacher Destroyer (Silver): It's always been a dream to defeat a PE teacher...
Platinum Trophy (Platinum): Congratulations on getting all the trophies!
Playing Favorites (Bronze): Aren't you happy to be surrounded by your favorite characters?
Puzzle Master (Bronze): Erase everything! Train that brain!
Raspberyl Version Complete (Bronze): You all graduate, today!
Reverse Pirates! Everything is Mine! (Gold): Reverse Pirates, yeah! Nothing is left in our wake...
Reverse Pirates! I Shall Take Your Innocents! (Silver): Reverse Pirates, yeah! We're taking all the Innocents with us!
Reverse Pirates! Your Treasure is Mine! (Bronze): Reverse Pirates, yeah! All that treasure's just for me!
Shopping Spree (Bronze): As a proud demon, I'll buy everything at the store!
Shut Up Already! (Bronze): I'll never stop talking!
Super Honor Student (Bronze): The HQ at this school is truly amazing.
Survival Class: Passed (Bronze): You truly are the Survival Master!
Tera Damage! (Silver): Even more training! Good job!
The Shamshank Redemon (Bronze): I'm just testing your loyalty.
The Towertastic Ten (Bronze): This is the epitome of a tower!
Treasure Hunter (Bronze): Don't your legs feel stronger from all that jumping?
Trophy Shopper (Bronze): I've been waiting for you in this Mystery Room!

Easier Homeroom Success
This will make it easier to pass topics in the Homeroom. If you press the X button just as the representatives say "Aye" the gauge on the right hand side of the screen will jump up much further (it plays a different 'dwoop' noise to cofirn if you got it). If you press X in time with the voting chances are the topic will pass.

How To Get Them All Diez Gentlemen
Each of the Diez Gentlemen can be acquired by starting a New Game+ while Mao is at at a certain level or above

Beyond X: Level 64
Bo Tie: Level 300
Breezy Satina: Level 700
Gorillian: Level 64
Goro: Level 400
Pauline: Level 600
Prinny Mask: Level 64
Se-to-oh: Level 500
Shyrone: Level 64

Unlockable Cameo Characters
Aramis: Clear Class World Command Attack with less than 100 commands
Asagi: Beat extra map 4
Axel: Beat extra map 6
Beyond X: Lose against Raspberyl on stage 1-5
Laharl, Etna, and Flonne: Beat extra map 7
Marona: Beat extra map 5
Master Big Star: Beat extra map 1
Pleinair: In Survival, get 7 Level Spheres and wish for the Mascot Character
Prinny Mask: Play main story again
Prism Red: Beat extra map 3
Salvatore: Beat extra map 2
Super hero Aurum: Finish 3rd Period of 'Raspberyl version'

Unlock the DLC Characters from the PS3 Version
To unlock these, you must beat the main game and reach a certain point in the side stories. Upon accomplishing the second condition, you get a message about the character wanting to meet with you.

Gordon: Beat Second Period of Raspberyl Mode
Jennifer: Beat Second Period of Raspberyl Mode
Kurtis: Beat First Period of Raspberyl Mode
Prinny Kurtis: Beat First Period of Raspberyl Mode
Thurdsay: Beat Second Period of Raspberyl Mode
Tink: Beat Third Period of Raspberyl Mode

Hero Prinny and Mid-Boss
Hero Prinny and Mid-Boss: Clear "First love!? Legend of the Super Delinquint" , then reach the postgame