Witches and Demons

A raunchy tale of witches for adults only. Witches are dangerous. Everyone knows that. Unexpectedly, and fortunately very rarely, a young maiden will turn into a witch. She will gain powers over animals and men, and eventually be able to summons demons from the fiery pits of Hell. As her powers increase, her nature turns to evil, no matter how sweet and innocent she began. This was well known in a time long ago, a time quite different from today.
The only good witch is a dead witch, so the old saying goes. A trip to the stake and a roaring fire was the fate of most witches. So why, when he chances upon a young woman freshly turned witch, would a young lord from Arendale save her from a mob of peasants bent upon her death, and then take her to his castle? Only by gagging her to prevent speech can he assure she can utter no curses. And he is forced to keep her hands bound behind her to prevent the removal of the gag.
So why does he go to such extremes and court danger? What does he plan to do with her?