Fictives are members of plural systems who identify as fictional races or characters. (Fictives should not be confused with fictionkin, who are usually, but not always, singlets who identify as fictional characters or species.) Fictives may or may not be walk-ins of fictional characters of species, and may or may not be members of a system who simply identify as a fictional character or species. Frequently in the case of walk-ins, fictives are exactly as they were in canon, given the general lack of life experience in this realm prior to joining the individual (or system) they now reside with.
Fictives can be very much like fictionkin, in that they identify as something fictional, which can be a specific character or a species. Some systems have reported walk-in fictives as being confused when they first enter the body, and in some cases, even in a state of panic. Other systems have reported very different circumstances, and therefore walk-in reactions can (and do) vary.
Fictives are always members of a plural system of any type, such as multiple systems, median systems, and all other forms of systems. Fictives are never singlets.