The Nine Swords Trilogy referred to the three novels," The Blade Is Hardened,"" Killer 13," and " All the Way West." The relationship between these three works was: 1." Assassin 13 " was the sequel to " The Blade Is Hardened ", which told the story of a young man who transformed from a school killer to a professional killer. 2." All the Way West " was a side story of " The Sharpen's Edge ", which told the story of a killer who accidentally discovered that he was a savior chosen by fate. 3." The Sharpen's Edge " was the beginning of " Assassin 13 ", which told the story of a teenager who grew from an ordinary student to a professional killer. Therefore, you can read the Nine Swords Trilogy in the following order: 1. Assassin 13 2. All the Way West 3." Unlocking the Blade from the Sharpen "