Here’s a short original story based on that idea: The PDF of the Silent Shadow
Curious, he downloaded it.
And in the corner of the screen, a text file updated in real-time. It read: "The true ninja does not hide in shadows. He hides in curiosity. Delete the file. Burn the computer. Forget page 47." Kaito closed the PDF. Then he unplugged his router, drilled his hard drive, and never searched for ninjutsu again. If you meant you want a (historical or fictional) in PDF form, let me know and I can recommend specific titles like The Ninja and Their Secret Fighting Art by Stephen K. Hayes or the Bansenshūkai . ninjutsu book pdf