Class

In the Disgaea series, every individual unit has a class they're a part of. Their class determines their appearance, weapon proficiencies, statistics, movement range, jump height, throw range and throw height.

Humanoid vs. Monster classes
Each class is classified as either a "humanoid" class or a "monster" class. Humanoid classes can equip any of the seven (or eight in Disgaea D2) primary types of weapon. Monster classes can only equip monster weapons, of which there is only one type of in Disgaea: Hour of Darkness, but since Disgaea 2: Cursed Memories, there is one type of monster weapon based on the attack stat and another on the Intelligence stat. Only humanoid classes can lift other units, though monster units can throw other units if a unit is thrown on top of them, and in Disgaea 5: Alliance of Vengeance, they can use Mon-Toss which allows them to throw units by themselves.

Since Disgaea 3: Absence of Justice, monster class units can use Magichange, which allows them to transform into weapons usable by humanoid units. In Disgaea 3 and Disgaea 4: A Promise Unforgotten, they have an extra Evility slot to use compared to humanoid units.

Class tiers
Generic classes have up to six tiers, each with higher stats and a different color scheme than the previous one. Prior to Disgaea 5: Alliance of Vengeance, the higher tiers are generally unlocked by reaching a certain level as the prior tier of that class, or reaching a certain level with certain classes. In Disgaea 5, characters can gain experience in classes, which results in an automatic upgrade to the next tier, and the unlocking of the next tier if not unlocked already, after enough experience is earned to master a class.

Weapon mastery
The rate at which a character gains weapon mastery is partially determined by the class of the character. Prior to Disgaea 5: Alliance of Vengeance, monster classes could not gain weapon mastery, but may keep some of their mastery if reincarnated from a humanoid class. In Disgaea 5, monster classes gain weapon mastery for monster weapons instead of humanoid weapons, and both humanoid and monster classes will gain armor mastery.

Reincarnation
Generic characters can change classes by reincarnating, which allows them to learn the abilities of another class, and keep their old spells, if their experience of each ability is high enough to stay learned. Characters acquired by playing the story and not created by the player cannot switch classes.