Lore wise of KND to be a KND operative you must be at most 12 years old and below as once a KND operative turns 13 they are then classified as a teen and are sent through the decommissioning process however since most hentai games are (correct me if im wrong) legally obligated to state that their characters are 18+ its best to say yes they are 18+. As for if the characters are original I believe "numbuh" 202 and numbers 78, 42, and 34 as well as most of the characters are from the show... your character, sandra deets, anabelle, and virgnia sims are all original characters (again correct me if im wrong) because I do not remember any of them being in the actual show.