One of the biggest draws to the Disgaea series is the amount of classes/characters available to the player. There are certain characters that will join your party during the main story or upon completing certain maps, but the rest of the units have to be created.
When creating new units, players choose one of many classes, which have different tiers. Note that all tiers are not unlocked from the very beginning, as you will need to level the previous tier to a certain point. In previous games, you had to reincarnate to switch to another tier, which reset your level back to 1 for the unit, but Disgaea D2 lets you switch tiers without having to reset your level.
