Exploding QFT: A Fan-Driven Lecture Series is a creative and educational quantum physics project that combines rigorous theoretical concepts with narrative storytelling drawn from popular culture. This third lecture, titled "Wigner's Friend and the Jusenkyo Trial", presents the quantum measurement problem through a courtroom comedy inspired by Ranma 1/2. Using the legal dispute between Ryoga Hibiki and the Jusenkyo Tourism Development Corporation, the lecture introduces observer-dependent knowledge, quantum measurement, identity, information flow, and Wigner's Friend. Characters including Ryoga, Ranma, Akane, Genma Panda, and Eugene Wigner are used to illustrate the distinction between internal and external observers, the role of measurement records, and the consequences of observer-relative facts. The lecture culminates in the humorous concept of "Optimal Defeat", where a formally successful measurement outcome produces a socially undesirable result, illustrating how information acquisition can fundamentally alter the structure of a system. All historical physicists, scientific concepts, and fictional characters referenced in this work are publicly documented and may be consulted through standard textbooks or English Wikipedia. This material is intended for educational and non-commercial use under a Creative Commons license.