Daughter to Demons (D2D)
D2D is an "urban fantasy" setting, in which ancient mystical forces lurk behind the ostensibly mundane façade of modern existence. A wide variety of mystical entities -- succubus, angel, satyr, salamander, phoenix, etc -- either make definite 'on camera' appearances or else are authoritatively asserted to exist. While it is not made clear how or why all these entities have elected to conceal their true nature at all times (as they must, or else the setting wouldn't be even ostensibly mundane), the evidence seems to imply 1 (one) supremely powerful entity which likes it that way and forces all the others to 'play ball'.
The first story in this setting is Daughter to Demons, in which a male human college student named Jack Renfrew is transformed into an extremely female succubus-like entity; changes her name to Jackie; and is very pleased to discover that she doesn't have to do the succubus thing. Ashes to Ashes, the lone sequel, throws Jackie into the thick of a murder mystery and brings an improbably high number of mystical entities into the action.
This setting was created by Jeffrey M. Mahr, who wrote both of the stories in it.