In any great story, one finds a protagonist and an antagonist. These may be one or many individuals. But it seems that humans tend to like reading books with such stories and watching movies with such stories.
Many times, the hero undertakes a journey and, in the end, the villain is defeated in most cases in the climax. It appears that there is something in the human brain which makes one want to read and watch such stories.
In writing any story, it is usually recommended to know the end before writing. Also, it may be good to start with creating a really good villain right at the outset.