A New Cycle is the in-game term used to describe the additional playthroughs of the game unlocked after reaching an ending. Despite starting the story over, all of the player's characters, their levels, assembly rank and their equipment will still be intact from the previous "cycle".
New Cycle in DisgaeaEdit
Characters that are not acquired until they are met in the story are removed from the player's team until they meet that same character again in the storyline (so for example, leveling up Flonne won't be of any use in the next cycle until you acquire her). Levels and equipment for those characters apply once they are added to the party: it does not alter their stats when encountered as monsters the player needs to defeat.
This is a way to easily play through the game's story at a rapid pace once one has acquired powerful characters. It also allows players to more easily attempt to unlock certain endings (such as those requiring no Ally Kills).
While assembly votes are generally retained, for unlocked worlds (Prinny Land, Beauty Castle, Alternate Netherworld, etc.) the player must spend the mana again to unlock these worlds even if they have already unlocked or even defeated them in the previous cycle.
What's more is a new cycle also allows for the unlocking of certain characters and modes in the later remakes, like in Disgaea: Afternoon of Darkness and Disgaea DS, it allows the unlocking of Etna Mode if you met certain requirements from your previous playthrough. Also, in Disgaea DS, the only way to unlock the playable Pleinair, as well as gain humorous commentary from a Prinny on the top screen during cutscenes, is to be on at least your second cycle.
In Disgaea 2: Cursed Memories and Disgaea 2: Dark Hero Days, a New Cycle is one of the requirements for some of the Bonus Characters. When starting a New Cycle in Dark Hero Days, you can also access Axel Mode as opposed to starting another game in Adell Mode. Note that if you do start a new cycle in Axel Mode, all story mode enemy levels, character levels and bonus ranks will be much higher than they would be if you use a code to play Axel Mode in the first cycle (Axel starts at level 100), but this effect does not stack and does not carry over to Adell Mode. (It may also be worth noting that Yukimaru's final special attack, which is only unlocked at a certain point in the story, will not remain unlocked in a new cycle.)
In Disgaea 3: Absence of Justice starting a New Cycle while having Mao at a certain level will unlock a special Diez Gentlemen character for your party, starting with Prinny Mask and giving you a new one every time you start a New Cycle.
In Disgaea 4: A Promise Unforgotten beating the game's normal story then starting an New Cycle allows the player to view the game's true god ending if the proper requirements are met. This feature can become a very useful tool to players that would like a second "go" at fighting such characters as Zetta. Continuing on a new cycle will also give you another attempt at stealing items off characters you were previously unsuccessful at snatching.
In Disgaea 5: Alliance of Vengeance, a new cycle is referred to in-game as a "Past World". Unlike all previous titles in the series, a New Cycle will carry over story characters, even if, at that point in the story, they had not been unlocked in the first playthrough. No new classes are unlocked through the new cycle, however it does also refresh the player's Quests, allowing the player to complete them a second time. Furthermore, the Carnage Dimension remains unlocked in a New Cycle, however the only stages available will be the carnage counterparts of levels currently accessible in the main story. A new cycle does not undo passed Assembly bills to fight Baal, increase the party limit, and so on. Additionally, all features (such as the Recruiter and Dark Assembly) that were not immediately usable in the early story on the first playthrough remain accessible. However, a new cycle also erases stage completion history, meaning that any bonuses granted from evilities such as "A Taste of Victory" will be reset to 0.
New Cycle in other gamesEdit
Phantom Brave originally didn't have a New Game+ feature until it's Japanese re-release. However with the Wii version "Phantom Brave: We Meet Again" the New Cycle feature was added so both American and Japanese Audiences can use it. The New Game+ feature lets you start at the beginning again and also lets you go to Another Marona Mode.
Makai Kingdom on the other hand makes it so you need to do a New Game+ to access many of bonus characters in the game (such as Alexander, Valvoga or Babylon). Further more, getting certain bonus characters forces a New Game+, giving you access to that character once you get back to Chapter 1.
Soul Nomad and the World Eaters also has a New Game+ feature. Doing so is useful for raising up a powerful squad of Troops (since you can't go back to previous levels after you clear them) and also useful for unlocking the game's numerous endings, as well as gaining the ability to play in the Demon Campaign. Some things can cause an instant New Game+ (such as using Gig's Full Power during the first fight with Fienne or beating Asagi.
Cross Edge also uses a New Game+ feature but with a slight twist. Characters do not retain levels and start from their original starting point. However, Titles and Souls are retained. Anything else (such as Weapons, Armor, Items and so on) can be retained but how much depends on the Difficulty setting of the original playthrough.