Vipin, whose family was erased in a GDC data purge, is driven by personal vendetta. Using an old neural hack inherited from his mentor, Dr. Aislin Yarrow (a legend who vanished after challenging the GDC), Vipin begins tracking the PDF’s digital trail. His tool? A sentient AI, Kali , embedded in his cortex, whose loyalties are as malleable as her code.

Next, I should consider the genre. Since it's a novel, maybe it's sci-fi or mystery. The mention of a PDF download suggests a modern angle, perhaps involving technology like hacking or digital theft. Maybe the story is about a protagonist trying to download a secret document or e-book that's being protected. The term "PKD" might relate to cryptographic methods if it's a sci-fi setting.

Characters: Vipin as the protagonist, a skilled hacker or programmer. The antagonist could be a rival organization or individual with opposing goals. Maybe include a sidekick who helps Vipin, or a mentor figure with experience in digital security. The novel PDF could be a manifesto, a revolutionary software, or a piece of evidence that could change society.

World-building: If it's set in the future, describe the digital landscape. How do people access information? Are there strict regulations? Or maybe a dystopian society where access to certain knowledge is restricted. The digital PDF might hold the key to breaking these restrictions.

Need to make sure the story is engaging, with a clear narrative arc. Include technical elements in a believable way without overwhelming readers. Balance action with character development. Maybe add some suspense and tension as Vipin's efforts are threatened.