Lunatica possesses the ability to increase her power by stealing life force from others. She may look and act like a child, but, in fact, Lunatica is actually several hundred years old.
Lunatica is quick to obey orders and not only doesn't hesitate to massacre her targets, but shows no mercy either, all in keeping with her simple, young age.
Lunatica is briefly mentioned by Ria at the beginning of Stage 1, with her being jealous of Lunatica's competence in combat. Ria calls Lunatica "Luna".