You are Laharl, a demon prince of the Netherworld who has been asleep for years. Laharl awakes to find that his father is dead and that he needs to claim his rightful place as Overlord of the Netherworld. Disgaea is Laharl solidifying his place and encountering new adversaries. The first thing that must be said about this game is that it is a very funny game. So much of the dialogue and character interaction is played for laughs while advancing the story.
Disgaea is a strategy RPG. You have a home base (the castle) which you can wander around in. It is a smallish castle. But it is from this castle that everything in the game starts. The actual gameplay takes place on "maps" or "grids" where you set your characters and move them into the best position, turn by turn, to do the most damage to the enemies or also maneuver themselves to attack your characters. This is a turn based game and you can think of the grid as a chess board. It's a chess board with height and obstacles and environment and certain tiles have special properties (attack +50%, invincibility, etc), but that is the way the grid plays out. From the castle you can also purchase items and weapons, go to the "Item World" in which you can fight inside an item to increase the item's stats, or go to the Dark Assembly where you get proposals passed to open new maps or get better stuff at the stores, or create new characters.
The name of the game here is fun. This is a fun game to play and I didn't notice how much time I spent playing until I checked the game clock. For those gamers who aren't sure if they would like a strategy RPG, this is probably the game to try because it is superior to the rest. For those who do like RPG and Strategy games, it doesn't get better than Disgaea. It's a game with lots to do. I spent nearly 80 hours on the game before finishing the story and there was plenty left to do. Good thing there is a "New Game +" mode to go back through the game and make different choices (for multiple endings) as well as working on unlocking those new maps and creating different character classes.