Question for Jews, why does it say that King David mated with a Succubus who gave birth to a demon Asmodeus?

The Kabbalah is a form of Jewish mysticism and esoteric teaching that emerged in the 11th century. It has no Scriptural basis and is not in harmony with the Torah or the Tanakh, which make up part of the Bible canon. So the stories mentioned here are based on tradition and myth, not Scripture.