Micky the Demon General is one part of a an overlord collectivly known as Dark Lord Valvoga. Micky forms the upper body, Dryzen forms the lower body in the form of a gigantic dragon skull with a glowing red orb within its mouth, and Ophelia forms herself into a head in a hole in Dryzen's skull, placing herself directly in the center of the "body".
While Micky is technically the one in charge of the body he is often manipulated by other Overlords, Dryzen and Ophelia in particular because of his timidness. When he finally learns to stand up for himself and make his own decisions his true form is unleashed in a more compact humanoid form.
Valvoga as a whole serves as the image for the Tera Star Spell in Disgaea 2.
Source: Wikipedia, "Makai Kingdom: Chronicles of the Sacred Tome," available under the CC-BY-SA License.