Disgaea 2: Cursed Memories has two unique Specialists called the Lover and the Bailiff. Neither appear in any previous or subsequent Disgaea games. The Lover is, generally speaking, a 1%-per-level everything-boost to the class, and the Bailiff is hardly a 'Specialist' in the normal sense, but rather interacts with the Dark Court/Felony system.
In Disgaea 2 , all non-Lover Specialists are Mothmen, Zombies, Ghosts, or Marionettes; they do not carry any weapons or armor, and their levels are in line with the other Item World inhabitants. The Lovers take on the form of their class-generating characters -- an Adell Lover looks like Adell, a Kunoichi Lover looks like a Kunoichi. Lovers of non-story characters will have no equipment and also be of similar level as the surrounding Item World inhabitants. Lovers of story characters will come equipped with non-stealable copies of the gear that the story character is currently wearing, and are also the same level, with the same stats and resistances, as said story character.
The player cannot use 2 stacks of Level 100 Firefighter to, for example, turn a negative Fire resistance, such as -50%, to 99%. An elemental resistances can be increased by a maximum of 100%, which equates to a Level 100 Firefighter/Aeronaut/Cryophile.
In addition to increasing resistance to the specified element, elemental specialists can also help increase the damage of attacks that utilize that element (ie, Cryophiles increase Ice damage).