Out of the Shadows: A Witching Pen Series Prequel. The Witching Pen, #7

It's 1985, and eighteen-year-old Katherine Green, twelfth-generation witch of her maternal family line, is a loose cannon. Grieving the death of her mother and estranged from her father - also leader of 'The Council' to which all witches are bound - she finds herself turning to a dangerous source for comfort: an incubus. Not just any incubus, but the king of the Shanka demon world, Darius. Seductive and relentless, Darius feeds on Katherine's rebellion like a vampire feeds on blood, with predictable and devastating consequences.
The only person with any hope of reaching her is Gwain, a fallen angel appointed to guard her by her father. But even he is struggling to make her see sense ... until an unexpected healing ray of light appears, demanding her courage, and changing the course of Katherine's future forever. This short dark fantasy novel explores Katherine's relationship with her father, with Gwain, and with the darkness inside her, also adding new depth to the events leading up to Elena's birth.
It contains themes of an adult nature, including sexual themes that may be triggering for some. It is probably best read after the four main books of The Witching Pen Series so the nuances of the relationships are understood better.