Two generations ago the Succubus Warlock of Asmodeus, Lilith, came to Faerun to impregnate herself with various mortals, intent on spreading her Infernal heritage throughout the Prime Material world. One of these fathers, a clever Satyr in the Moonwood (called the Glimmerwood by outsiders), successfully tricked Lilith after their son's birth and stole the child away, leaving an irate but impotent Succubus Warlock of Asmodeus far behind.
Meanwhile, in a more distant, more remote part of the Moonwood than the eyes of humankind see, The Princess of Swan Maidens was wed to the Prince of Huldras in the hope that their offspring would become a great monarch of Fey in the Moonwood. The daughter they bore showed all the potential of true nobility until the drow, helped by the Night Hag, Sanguine Agatha, kidnapped the girl Fey.
By the Luck of the Fey, or the Fate of the future, Sanguine Agatha and her drow took the girl to a mountain cave in the Spine of the World where a certain Satyr and his young son, the son of a Succubus Warlock of Asmodeus, had been living in hiding.
The ensuing battle saw the Satyr being helped by Dwarven allies with whom a friendship had been made, the end of which saw the drow defeated, Sanguine Agatha fled, and the Satyr killed.
The young boy Cambion, son of a Succubus and Satyr, and the young girl Fey, daughter of a Swan Maiden and a Huldra, met and were raised together by dwarves in The Spine of the World, just north of the Moonwood.