The King's Shadow

Edmund Pevensie is a bit reckless. He's good at what he does. But he's reckless. Tired of Edmund almost dying, Peter engages a bodyguard for him in the hopes that with a guard watching over him, Edmund will start being more careful. Edmund hates the idea but after having his butt saved on the first night, he decides to give it a shot. The bodyguard doesn't speak, he's covered in black from head to toe, except for his unnervingly silver eyes and nobody knows who he really is or where he's really from. But he's good at what he does. And despite what Edmund may say, he does need a body guard.
It doesn't take long before the two become closer and over time Edmund comes to know the person beside him as more than The King's Shadow.
(WARNING: Plot twists abound within and I swear the only reason it doesn't sound better is because I can't say anything more without giving away important elements to the plot so sorry)