Unlike Nippon Ichi's previous games, Disgaea 2 is on DVD-ROM and has an animated opening movie.
Currently, a manga based on the events of Disgaea 2 is being released.
Fifteen years ago, a powerful Overlord by the name of Zenon appeared on Veldime and cursed its human population. Since then, all its inhabitants became demons and were to remain that way if the curse was not broken. However, a young man named Adell was the only human unaffected by the curse. Wanting to save his family and return them back to their true form, Adell decides to defeat Zenon. Adell's mother, a summoner, tries to summon Zenon and failed, and instead summoned Rozalin, Zenon's daughter. They later go on a quest to find Zenon and return Rozalin to him, and then defeat him so that the curse would be lifted, and so his family would be human again.
After a battle with the "rest of the Snow Clan", who were turned into Ghouls, Etna and her Prinny lackeys show up. Etna then kills the Ghouls, and walks up to Zenon, about to fight him. Axel then stays behind to film the whole battle. The next day, Etna comes to Adell's house, proclaiming that she has defeated OverLord Zenon, but was wondering why her title was not [Goddess of All Overlords] or even just to [Overlord]. They then conclude that the Zenon that Etna killed was a fake. Adell, Taro, and Hanako's mother then comes out of the house, suggesting to try and summon Zenon. Adell then said, "Wouldn't that take years to prepare again?". She then says yes, but that there are other conditions to make it easier. Since Zenon is a demon, she'll attempt to summon "The most Powerful Demon". But they are missing the key ingredient, an [Overlord's Nail]. Mom then mentions that an equally powerful [Demon Lord's Nail] would work out just fine, They then looked for and found Etna in Alche City. Etna then gives them a fake nail and as a result, is summoned in Zenon's place. Etna finds she has now lost all of her levels in the summon and decides to join Adell and the others to go after Etna's infamous Prinny Squad who now work for a prinny called Big Brother, who turns out to be Fubuki, Yukimaru's elder brother.
The group then proceeds to Shinra Tower to get herbs from Old Man Geo in order for Etna to regain all her levels. But when they reach the top of the tower, they learn that Overlord Laharl ate them because "he was hungry". He then defeats Adell and the others. He saw Rozalin's seal and then attacked it, causing it to shatter. The seal was there only to keep Zenon's blood from coming out and once gone Rozalin becomes incredibly powerful and has a complete personality change. After she defeats Laharl the seal reforms itself. The next day they find out that Fubuki who was still badly hurt, went after Zenon. After Hanako & Taro find out the location of Zenon's castle they go to challenge him, but they were forced to fight the Mask servants of Zenon before they could. Once they are half way to Zenon they help Fubuki in his battle against some monsters because he is too weak to help in the final battle as the group finally came face to face with the Fake Zenon who transformed into a powerful Demon form. 
After the battle Rozalin broke her seal as the fake told them she really was Overlord Zenon (the real one) as she killed the fake one out of life itset...
The game has multiple endings. Depending on the way the game was played up to this point, Overlord Zenon (Rozalin) takes over the world, Tink becomes an Overlord himself or Adell will kill Rozalin, then become possessed by the true Zenon's spirit. It may also be noted that, on the Good Ending, Adell kisses Rozalin and one year later Axel becomes very unpopular again, Yukimaru & Fubuki will rebuild their clan, Tink will become his old self again as Taro is at home with his mom & Dad who are human again & Hanako will became Etna's "Student" and serves Laharl with her. (The "Good" endings are the only endings canon for future developments in the Disgaea series or in cameo roles for future Nipon Ichi games of other series. Eg: Prier from La Pucelle being in both Disgaea 1 and 2 as a secret stage.)
At the beginning of each chapter, a new area is unlocked. Each area consists of multiple maps which must be beaten to advance to the next chapter. Talking to the gatekeeper of Holt will give players the option of exploring the new area or repeating any maps that have been beaten. Many maps also have cut scenes. Scenes at the beginning and end of each chapter cannot be skipped.
Three merchants from the RosenQueen Company sell weapons, armor, and consumable items. The Netherworld Hospital revives characters and replenishes Hit Points and Skill Points after battle. The messenger hands out subpoenas, and the dark secretary, item worlder, and gatekeeper offer access to the Dark Assembly, Item World, and area maps respectively.
Players have a large degree of freedom to proceed through the story at their own pace and with their own style. Because the Item World and Dark Assembly are available soon after the beginning of the game, there is not much more difficulty in leveling up very high-powered characters and items in Chapter 1 than there is in Chapter 13.
Demons in humanoid form. These classes can use any of seven human type weapons, although the speed at which they learn depends on weapon proficiency. Humanoid classes can pick up and throw allies, enemies, geo symbols, and treasure chests. Warriors, archers, mages, and thieves are some available classes.
Demons in a more monstrous or less humanoid form, but some story characters that are humanoid are considered monster class instead. Monsters can equip either of the two monster type weapons. Monsters cannot lift or throw, but can be picked up and thrown. Zombies, dragons, golems, and prinnies are some available classes.
What makes Prinnies special is the fact that if a Prinny is thrown it will explode, inflicting damage. A special monster class, they appear to be stuffed penguins with wooden peg legs and small bat wings. A Prinny damaged by the explosion of another Prinny will itself explode. The special character Kurtis, whose class is Defender, is also a Prinny and will explode when thrown.
1 - Story characters will join the player as one advances the story or completes side quests.
2 - New characters can be created in the dark assembly using mana. It costs a minimum of 1 mana to create a new character, and new characters have different proficiency level they can start at from Good-for-nothing to Genius. Additional stat points can be given as characters reincarnate.
3 - Enemy monsters can be captured by throwing them onto the base panel. The rules for capture are that the characters in the base panel must have a combined level greater than the monster and that the monster must be one that can be created at the Dark Assembly. If either of these conditions are not met, the base panel is destroyed and that all characters in the base panel are killed.
Ten characters can participate in battle at a time, exhausted characters can be swapped back into the base, and the game allows a huge roster of generic characters in reserve to encourage using a variety of characters.
There is also a special version of reincarnation for characters who have obtained felonies in the game. Non-story characters have the option to reincarnate as a prinny once they have obtained at least 200 Mana. Reincarnating into a Prinny is the same as normal reincarnation except that their felony counter is reduced to 0 and that the character must become a Prinny until they have obtained at least 400 Mana and passed the "End Prinny Reincarnation" bill at the Dark Assembly. Story line characters do not have this option, instead they have the "Reincarnate to Atone For Sins" option at the Dark Assembly. This is also the same as normal reincarnation except for the fact it reduces the felony counter to 0. This option can be used when the storyline character has at least 400 Mana.
Once a resolution has been chosen, the view changes to a large auditorium with randomly selected senators. Each senator has a disposition toward the character proposing a resolution. This is the Netherworld, so it is perfectly acceptable to bribe senators with items in the item bag. Giving a senator the right items will improve their disposition toward the character. After bribing, senators will vote based on their disposition. If the yeas beat the nays, the resolution passes. Even if a bill loses the vote, the player can choose to "persuade by force". A base panel appears and the player can attempt to beat the opposing senators. If all opposing senators are killed, the resolution will be passed. Using "persuade by force" with lower level characters is very dangerous, as senators are more powerful than lower levels can handle, and losing means game over.
New to Disgaea 2 are the Legendary Senators, a special type of Dark Assembly senator with various abilities, all of which will radically alter the Assembly environment. Legendary senators have a very powerful voice (their votes count for far more than any other senator) and they will all create some sort of effect before casting their vote. For example, Legendary Senator Ares will strike an adjacent senator on his row, blowing away all senators on that line and eliminating their votes. Legendary Senator Venus will emit a magical aura that will force all adjacent senators to vote along with her, regardless of their dispositions beforehand. While bribing the Legendary Senators alone may not pass a bill for sure, not bribing them is nearly a surefire way to ensure a bill will fail: attempting to "Persuade by Force" with a Legendary Senator in attendance leads to a fight which the player is very likely to lose, if the legendary senator votes against the player, as all Legendary Senators are at least level 1000.
Additionally, as the game carries on, Adell can also gain access to the proposal of "I Want To Become A Senator". If passed, Adell will become a senator and can sit in and vote on special assembly sessions, such as raising the voice power of different parties. When Adell first becomes a senator is voice is 30. The player can increase his voice by passing the "I Want More Voice Proposal". Each proposal passed increases Adell's voice by 30 points to a maximum of 120.
In addition, all weapons and equipment are now a little more balanced out like the character classes to prevent them from being too overpowered or too underpowered. Specialist population slots have also changed. Normal items can only hold 4 residents, Rare items can hold 5 and Legendary Items can hold 6. However, the population cap can be increased by defeating the Item Kings/Item God and passing the "Increase POP" bill at the Item Assembly.
Disgaea 2 offers many new options to improve the chances of passing a resolution. Instead of an assortment of monsters used in Disgaea HOD, only six types appear on the senate floor. They are organized into six parties by their monster type. Each party has either a Weak, Medium, or Strong Voice. Senators with Weak Voices get 10 points in the vote, Medium Voices get 30 points, and Strong Voices get 50 points. Parties with the same voice oppose each other. Cell phones can be used before entering the Dark Assembly to influence the parties. Once Adell becomes a senator, he can attend special assemblies to raise the voice power of the different parties. If the "I Want More Voice" proposal is passed, that parties voice is doubled.
The Orc Party likes girls. All female characters who propose bills at the Dark Assembly will have a higher standing with them. They oppose Ghosts.
Ghosts tend to sleep through voting sessions. A sleeping character will not vote unless awoken with a "Bomb" item, which also decreases their disposition towards the characters. They oppose Orcs.
The Mothmen Party likes Monsters. All monsters who propose bills at the Dark Assembly will have a higher standing with them. They oppose Holy Dragons.
Holy Dragons will not accept bribes. Any bribes offered will lower their disposition towards you. They oppose Mothmen.
Baciels always show up to the Dark Assembly Drunk. Drunk characters vote erratically and are very tricky to bribe, having a hard time recognizing the items they are given. They oppose Wood Golems. (If a Baciel or any other senator is Drunk when "Persuade by Force" is chosen, they will begin the fight affected by the Amnesia ailment.)
Wood Golems oppose Baciels.
On occasion extremely high level humanoid senators will appear. They have no affiliation with a party but usually have the largest pull. Additionally some have abilities that alter the final vote. Legendary Senator Venus(an Archer) has the power to make other senators near her change their votes to match her own, Legendary Senator Ares(a Heavy Warrior) will attack any senators to his left and knock them completely out of congress, removing their votes, Legendary Senator Morpheus (a Red Skull) puts nearby senators to sleep, removing their votes from the final tally, and Legendary Senator Tengan (A Geo Master) may occasionally appear and ask for a specific item (often one that isn't in the player's inventory). Handing it over to him (when available) will cause him to immediately vote in your favor, while ignoring him (or not having the item) causes him to jump up and down in rage and vote against the player.
Each bribe can be a MUST HAVE!, INTERESTED, SLIGHTLY INTERESTED, NOT VERY INTERESTED, or DOES NOT WANT. The more interested a senator is, the better the disposition bonus. Interest in an item is based on rarity and differs from one senator to another. The bribe will have a strong effect on the senator receiving it, and a weaker effect on senators in the same party. It will also have the opposite effect on all members of the opposing party.
For example: Adell bribes an Orc Senator with a Mint Gum. The senator's disposition improves from Either Way to Leaning Yes. At the same time, all Orcs improve their disposition by a slight amount. All Ghosts (the party opposing Orcs) give a slight penalty to disposition.
Some items used as bribes can have special effects on senators such as waking, sleeping, intoxicating and sobering. These items are rare and hard to come by early in the game. There are also purchasable items that will always have a MUST HAVE! or INTERESTED status regardless of who they are shown to.
Another returning feature of the original Disgaea, Item World is the world within every item in the game. In order to enter Item World, the player must talk to the thief near the three merchants. The item must be unequipped and be in the inventory. Once inside the Item World, the player must go through at least ten randomly generated maps. These maps can either be cleared by defeating all enemies on the field or by entering the red dimensional gates, which transports the player to the next map. The maximum amount of floors all depends on the rarity of an item. Common items will have 30 floors, rare items will have 60, and legendary items will have 100. Although items can have a max of 100 floors, the level of an item can exceed the level 100 limit through the use of certain mystery rooms in item world. In order to leave the item, the player must choose the option to leave after completing at least 10 floors or must use the item Mr. Gency's Exit (Emergency Exit).
Most items will contain specialists. These specialists can increase certain stats or have special abilities, such as raising the levels of other specialists or creating specialist offspring. While in item world, a specialist may appear. If the player defeats one, it is subdued. Subdued specialists can be moved from item to item. Specialists can also be combined to make room for more specialists. There are also item bosses, which appear on the 10th level of every item and will usually appear in the middle of the stage, sometimes on higher ground. Item bosses do not function like normal specialists as they cannot be viewed outside of the item nor can they be moved. However, defeating an item boss will grant the item bonus stats, alongside the normal stat gain, upon leaving the Item World.
Disgaea 2 also features several new specialists. Perhaps the most unusual added specialist is the "Lover," which does not come on a new item, instead spawning on an item when a given character uses the same item for a large number of battles. For example, if a Prinny uses the same weapon for long enough, a Prinny Lover may eventually appear on the weapon. Lovers give a base 1% boost to all stats of the user as long as they match the user's class or monster type, up to a maximum of 25% from a Level 25 Lover. Also, Lovers amplify the passive skills of their users, usually by one percent per level of the Lover. A Wood Golem monster, for example, regains 20% of his max HP every round. For every level of Wood Golem Lover attached to his items, however, he regains an additional 1%, up to a total of 45% per round with a level 25 Wood Golem Lover. This is every bit as incredible as it sounds, as Wood Golems have an amazing amount of HPs and are extremely hard to kill even without the 20% regeneration, much less a Wood Golem which regenerates nearly half of its health per round.
On each floor, with the exception of the item boss floors, there is a random chance that pirates will appear at the end of the enemies' turn. There are 18 different types of pirates. The pirates may be a group of enemies or a single yet powerful foe. With the exception of the final two pirates, all pirates carry a treasure map. Upon defeating a pirate who carries a treasure map, the player will obtain a treasure map. There are sixteen treasure maps, and if the player is able to collect all of them, he or she will have access to the Land of Carnage. In addition, certain pirates may have useful bonuses such as extra specialists and a portal that will allow the player to skip several floors.
While going through Item World, a player may encounter a yellow-green dimensional portal. This portal will lead to a Mystery Room. What is contained in the mystery room is random. There are a total of 14 Mystery Rooms, each one containing something different. One important thing to note is that if a player comes across a store, they can only access that store once per visit. Since the Mystery Room is not considered a map, the player can access their inventory/warehouse freely. Additionally, most to return to the item world, a player must talk with the Ghost or complete the battle (if there is one). Additionally, once a player runs across a Mystery Room, and regardless if the player enters or not, the gate will not appear again for at least another 3 floors (except for boss floors).
After at least 10 floors, an Innocent Town may appear. These towns are similar to Holt. The player can heal his/her allies here, find treasure chests, or talk to the residents in town. The town also contains its own Dark Assembly, known as the Item Assembly, which contains bills that can power up the item even more or add properties that the item normally wouldn't have, such as added Movement. It is also possible to use the Item Assembly to create a name for the item. To leave the Innocent Town, the player must talk to the ghost. The player can choose to go further into Item World or return to Holt. There are other properties of the Innocent Towns such as wanderers that include Prism Orange, Axel (Akutare), and Prinny Kurtis. That aside, the most substantial random appearance in the Innocent Town is the Hide-And-Go-Seek Prinny. The Hide-And-Go-Seek Prinny will offer that if you find him a number of times, he will give you a substantial prize.
During the game, the messenger, located next to the Dark Assembly secretary, will have subpoenas. These subpoenas state the crime a character has committed (eg. Too high HP) and contain a bailiff specialist. The level of the bailiff indicates which floor the player can enter the Dark Court. In order to get to the Dark Court, the player must enter the Item World of the subpoena. Once the player reaches required floor, a blue portal will appear on the field. The player must choose a character (does not have to be the character specified on the subpoena) to enter that portal. Once entered, the character will be judged by the Dark Court and be pronounced guilty of their crime. Depending on the crime, the character will gain a certain number of felonies and will also be rewarded with either items or HL. Felonies will actually benefit the character. A character with a lot of felonies will pass bills in the Dark Assembly more easily. Characters with felonies can also gain more experience points depending on the number of felonies a character has. Although only 99 felonies can be shown on a character, the effect of felonies will be maxed out at 300 felonies. Although it is not necessary, Atonement Reincarnation will make it easier to keep track of the player's felonies, as Atonement Reincarnation will remove the felony stamp, but not the effects.
Note: If a character is carrying other characters upon entering the Dark Court, the felony is granted to the character and all characters he/she is carrying.