Disgaea 3 is the third video game in the Disgaea series by Nippon Ichi. It was released on January 31, 2008 in Japan for the PlayStation 3 video game console.

The game takes place in a Netherworld School called the Maritsu Evil Academy. In this demon school, a good student is one who engages in delinquent activities such as ditching classes, or not doing homework. The student who participates the most in this kind of activities is known as the Honor Student, while demons who arrive to class early and do their homework are known as delinquents. Mao, son of the chairman, has not once attended class since the beginning of school and is known as the honor-student of Maritsu Evil Academy. His ambition for the future is to overthrow his father, who also happens to be an Overlord, and take his title for himself. After reading a few volumes in his manga, Mao comes to the conclusion that "heroes are the ones who defeat devils". From that point on, Mao resolved to become a hero himself, convinced it will help him achieve his goal.

Eventually, Raspberyl, the delinquent of the school, learns about Mao's goal and begins to worry. If Mao were to achieve the title of Hero, then it would endanger her position as the school's "Number One Delinquent". She makes up her mind to follow Mao, stop his plan, and once again secure her title. However since Raspberyl is a demon delinquent, she tries to solve the problem without violence and talk him out of it instead. Seeing this from a distance, Almaz, a hero himself, misunderstands the situation and tries to save the day. Mao accepts the challenge and defeats him, stealing Almaz's title in the process. With the title of Hero, Mao believes he is one step closer to defeating his father and achieving his goal of becoming an Overlord.

(Wikipedia)

UNLOCKABLES

Secret character classes

Reach the following goals to unlock the corresponding character class.

Female Archer: Level 15 Female Fighter and level 15 Female Healer.
Female Ninja: Level 30 Female Monk and level 30 Female Magician.
Female Samurai: Level 35 Female Fighter and level 35 Female Archer.
Geo Master: Level 20 Fist Fighter and level 20 Healer.
Gunner Female: Level 15 Female Thief and level 15 Mage.
Gunner Male: Level 15 Male Thief and level 15 Mage.
Heavy Knight: Level 15 Male Fighter and level 15 Fist Fighter.
Magic Knight: Level 25 Fighter and level 25 Mage.
Majin: Complete the tutorial again on a cleared saved game file.
Male Archer: Level 15 Male Fighter and level 15 Male Healer.
Male Ninja: Level 30 Male Monk and level 30 Male Magician.
Male Samurai: Level 35 Male Fighter and level 35 Male Archer.
Masked Hero: Level 45 Thief and level 45 Gunner.
Monster Tamer: Level 15 Female Fighter and level 15 Fist Fighter.
Ninja Female: Level 30 Female Fist Fighter and level 30 Mage.
Ninja Male: Level 30 Male Fist Fighter and level 30 Mage.

Here's a gameplay trailer: