The Dark Sun is a gameplay mechanic in Disgaea 2: Cursed Memories.
It only appears in the Dark World, where it has random effects depending on the map entered. These can be viewed in combat by looking at the Dark Sun Report to see its rotation with the Square button (X on an empty square in the PSP remake) or the Sun Report button on the menu. Many of these effects are negative, such as damage or Status Ailments, but a few are beneficial. On some maps, one of the effects of the Dark Sun will result in a Game Over event occurring causing the player to immediately lose when the specified turn is active.
The Dark Sun has a limited HP count, and its remaining HP percent is shown on screen underneath the Bonus gauge. The Dark Sun can be destroyed by choosing the "Ascend" command in a character's menu. This will sacrifice the character and prevent it from further taking part in the battle. Even if a character fails to destroy the Dark Sun, they can still lower its HP, which can allow another character to take it out. However, if the character has felonies attached to their name, forcing them to ascend will not cause damage to the Dark Sun, instead increasing the level of enemies on the map by their current Felony Count total. It is impossible to order a character to ascend if the character is the only one currently in the map and it is not possible to dispatch more characters by using the Base Panel, either if the Base Panel itself is destroyed or the dispatch limit has been reached due to elimination of other characters.
Enemies can also ascend to the Dark Sun. Enemies can sacrifice themselves and increase the other enemies' levels by the number of levels the ascender had. For example, an ascending level 2 enemy will increase the level of other enemies by two. Note that characters with Felonies power the enemies in a similar way if they ascend, powering enemies up by their Felony Count total rather than their level.
The number of stars (As well as the sun's facial expression) seen in the beginning of the stage shows how hard the Dark Sun is to destroy. This ranges from 1 star (Weakest, calm face) to 50 stars (Strongest, extremely angry face).