Throughout human history, emperors and kings were obsessed with finding ways to prolong their lives and by extension their reigns. For example, Henry VIII often drank wine that was flavored with gold and gems that were thought to extend his lifespan. In fantasy such as The Dark Crystal, Harry Potter, and Star Wars, characters have found forms of magic that could prolong life. One of these methods involved draining the life force of other organisms and transferring it to oneself. Such a method could add years or even decades to your original lifespan. I am thinking of depicting the main character of my third fantasy book using this method by draining the life force out of livestock. With the livestock drained of life, the character’s cooks and servants would promptly prepare them for that night’s supper. So with this method, the main character would prolong his life and increase his pantries with salted meat. Win win!