The design of the Xuan Yu Needle draws inspiration from the Eastern aesthetic of assassination, where “leaves serve as blades, concealing deadly intent.” Shaped like a delicate green feather, its emerald hue evokes the fresh leaves of a forest—seemingly elegant and harmless, yet secretly imbued with potent poison. The needle’s body is intricately patterned with feathery veins, which not only reinforce its structure but also provide concealed compartments for storing highly toxic substances. The sharp barb at the needle’s tip can be deployed in a swift, close‑range strike—or cleverly disguised as a hairpin, hidden within the wearer’s locks. The aged, weathered finish, reminiscent of verdigris on bronze, gives the needle the appearance of a fragmented feather left behind in an ancient woodland: silent and unassuming, it claims lives without warning, perfectly capturing the essence of this stealth weapon—“still as an autumn leaf, yet swift as a thunderclap.”