This is by far one of the hardest achievements in the game. After defeating Zetta you will unlock this rematch with Pringer X. This battle with Pringer X is a lot more difficult than the previous. Be prepared this one will be a grind. We will start with Preparation.
-LVL 9999 Thief + Stealing items (Bought at Rosen Queen Snack Shop)
-Land of Carnage (Unlocked Via P Flonzer Ship Parts + 40% of X-Dimensions Cleared)
-Puppy Paw Stick (Found by Disciplining 1000+ Nekomata or Item World Via Sphere collector Mystery Room)
-Battle Suit Ally
-LVL 300 Rank 38+ Weapons
-LVL 300 Trapezohedron (Land of Carnage Arcadia Item World Floor 100)
-Innocents (Will go into more detail later)
-Lots of Gency Exits (Item World\Char World)
Obtaining the Puppy Paw Stick
You can find these in the Item World through a rare Mystery Room with a Cockatrice with a black beak. Do not confuse this room with the Senator Bribing Room that also has a Cockatrice. You will know the difference because the Cockatrice here will have a black beak and there will be no boxes. The Second Way and easier approach is to Capture and discipline a Nekomata. Use the Cheat shop and set the difficulty to max and play X-Dimension Stage1-1. That will have a high level Nekomata that you can capture and Discipline.
-Valvatorez must be a higher level than the Nekomata
-You much have the Class and Tier of the enemy you are going to capture
-You need to have a Discipline Room
Discipline and save before asking for treasure as the treasure loot is set once you ask for it. Then simply go to the level and open the chest. Quit and reload if not the Puppy Paw Stick.
Item and Innocent Duplication
Main reason we got the PPS (Puppy Paw Stick) is so we can duplicate items. To make things even more ideal Innocents can be duplicated as well. If possible equip the PPS on an Axe wielder as they get a 20% chance to steal from a defeated enemy. On anyone else its 10%. The goal here is to get a bunch of LVL 300 Items and duplicate them with innocents on them. The Land of Carnage Item World is pretty intense so you want to be able to hold your own. Level up you best items LVL 300 remember you can Duplicate items so if you have multiple sword users, just level up the best sword you got to 300 with 6 More ATK Bills and follow my duplication guide below.
To Duplicate grab the LVL 300 item you want and fill it with any Innocents you want. I recommend all the Single stat Innocents (Gladiator, Dietician, Marksman ect) as well as Elemental resistances (FireFighter, Cryophile, Aeronaut), Statisticians (EXP Bonus), Professionals (Crit Chance Bonus), Fencers (Increase stats on Sword users, there are Innocents for all weapon types) and Managers. Do not worry if they are not maxed. Open the Status page and Press X for Dispatch. Set one group to your PPS user and your Battle Suit. Equip the Item you want to duplicate to the Battle Suit and nothing else.
Load up Stage 1-1. Bring out the Battle Suit and use his "Run Wild" Skill. This make him a neutral unit. Bring out your PPS user and kill the Battle Suit. If you are lucky you will get a popup saying you took the item you equipped on the Battle suit. If that is the case, kill the remaining enemies and clear the stage. If not quit and select retry until you get the pop up.
Early on with Innocents it will be a bit frustrating as you are going to need to unequip the item and combine the innocents until they are maxed and make sure the newly combined innocents are on the item to make the next combine even larger until maxed. Once you no longer need to max Innocents you can just keep starting Stage 1-1 over and duplicating items and then just store the innocents in the resident storage.
You will want to do this when you get the Trapezohedron as well but dont do it until its LVL 300 and maxed.
Leveling up and Char World
In order to not only Defeat Pringer X but to get through LoC Item World you will need much stronger allies. You can Level up quickly by duplicating a maxed Statistician 8 times to fill one piece of Legendary equipment. Use that one piece of equipment as a LVL booster. Equip it to the Character you want to get to LVL 9999 and complete LoC Mt. Ordeal Stage 4 with them. Utilize the Medic to use that Character to attack twice in one turn. Use the Cheat shop to help you by increasing the XP if needed and to heal automatically when returning to Base. Fist users can clear the map in 1 attack with a Giant Fist Magichange + Big Bang Attack (Learned in Char World or Fenrich LVL 500). Warriors also posses a skill to increase ATK by 100% that can help any character with this. Some Characters are tougher to do this with than others so utilize the Training Evil Symbol. Place those hard Characters in the squares and place the Character you are boosting as the Leader. Leader should always have the XP Bonus equipment. The attacking Character generally maxes out after 3 clears. Use your Thief as one of these Characters so you can max her out.
Once all your mains are maxed. Head to the Char World and clear it with each Character. This can be done in a couple mins by ignoring the Geoblocks. Clear the geoblocks in Stage 1 if you need the Tier 7 and 8 skills for that character, other than that just head to the exit and kill the gate keeper and leave. Having High movement is very useful here. If you see the Floor clearing Geoblocks feel free to destroy those for a chance at extra Aptitude bonuses. Take advantage of Stage 9 and increase whatever you went in for and on Stage 10 Kill all the enemies for a Clear bonus and you will get a Gency exit as a prize. Repeat for all your main Characters until you have no more hosts left. You can omit the Thief from the Char World. We just need here at level 9999 unless she is part of your main party.
Reincarnate and repeat until you have 67-70 Gency Exits. Always reincarnate as Genius.
Getting the Trapezohedron
The only way to get a Trap is to Steal it from an Item God 2 since we cant defeat Baal to steal it from him. You can Steal a Legendary Arcadia from Pringer X if you defeat him in the regular world. If not you will need a Legendary Maki Wars to LVL up to 300 then steal a Legendary Arcadia on Floor 100 of LoC and then repeat with the Arcadia to get a Legendary Trap. The way to do this is to get to LVL 99 and Gency out. We do this because if you gency out at 100, the Item God wont have the item when he goes back. Save your game after exiting and head back in. On Floor 100 check the item God he will have the next ranked Item on him but the rarity is random. Quit to Title and retry if not legendary. Once you have one that is legendary you want to get you thief behind the item God as you have a higher chance to succeed from behind and steal the item.
Once you have a Trap do the exact same thing but at LVL 100 kill the Item God then Gency Out. You will get a stat increase every time you kill the Item God so you want to enter, kill the item God and then gency out again. Attack the Item God from Behind to increase your chances of hitting. Doing this 67-70 times will max out the stats on the item at 2.1 million. You can complete 4 stages the Reverse Pirating before doing all this as well to hit LVL 300 first, Just dont finish Stage 100. For the Bills on the Trap Pass 5 move builds and 1 Jump. That will give you characters a 15 Move and 30 Jump Boost for 3 Traps total.
Once Maxed. Duplicate it so you have 3 Per Character. Fill it with the Innocents you want. Make sure to get a Weapon Innocent in there like Fencer.
A Maxed Fencer(500) gives the Character a 500% Boost to stats on a character with a Sword.
A Maxed Professional(100) Gives you a 100% to land a Critical
Fill the rest with Maxed Marksman, Gladiators, Coach ect (19998) to max out your stats.
Head to LoC and initiate the Battle.
If you did not Steal the Arcadia and kill Pringer X the you will just be battling Pringer X and you with wreck him. If you did you will be faced with 8 Pringer Xs. Now this battle is harder than the other as you will only be able to use a specific skill on the enemy once. Doesnt count if it misses but it carries across all 8. So if you kill one with one skill, you cant use it on another. You should be able to one shot all 8 at this point so just use different skills for each character. Be sure to avoid Elemental attacks.
The achievement will pop upon killing just one of them.