Actors are the active elements in the situation-independent part of the Unconventional Conflict Ontology. The Actor Ontology has four Actor categories and 11 Actor subcategories. Each of the 101 Actor classes is connected to at least one Actor subcategory by an is-a relation. The categories and subcategories describe types of Actor elements. For example, the distinction among individuals, significant groups, and demographic groups, described in Chap. 2, is made at the category level, with refinements made at the subcategory and class levels. Figure 3.1 provides an illustration of individual actors in conflict. This chapter describes the organization of the Actor ontology and all of its elements, along with the types of Metrics associated with each element.