As Succubi are raised among Humans, a Succubus may never discover that it is one; she might never come to understand why men find her irresistible, or indeed why men die during intercourse with her. She will even appear to them in dreams where she acts out their greatest fantasy. Once a Succubus discovers what she is, and feels rejected by her inability to form real meaningful relationships, she will embrace her demonic nature and seduce and kill men.
Other supernaturals such as Ghosts, Vampires and Werewolves apparently cannot differentiate Succubi from Humans as they can each other, possibly due to Succubi's half-Human nature.
- It is rumoured that the leaked Rook emails mention that the Department of Domestic Defence are aware of a possible Incubus; Incubi are regarded in mythology as the male equivalent to Succubi.
- Some fans have suggested that Succubi may be classified as Type 5.
- It is unknown how common or rare Succubi are. They are most likely very rare like Zombies because only one has appeared in the entire series.