Dr. Yung, later unmasked as the enigmatic "Mirage Master," was once a scientist at the Pokémon Institute before his expulsion for unethical experiments in artificial Pokémon creation. Disgraced and embittered, he channeled his resentment into developing the Mirage System—a holographic technology capable of generating customizable Pokémon with abilities surpassing natural limits. Concealing his identity, he lured Ash, Misty, and Professor Oak to his lab under the guise of a demonstration, only to seize control of the system, kidnap Oak and a former colleague, and initiate his vengeful scheme.

His ambition centered on synthesizing a Pokémon devoid of weaknesses by merging data from global databases, including Pikachu’s forcibly extracted memories. This culminated in Mirage Mewtwo, a weapon engineered to dominate all challengers. Dr. Yung exhibited cold indifference toward both organic and artificial life, dismissing the sentient Mirage Mew as defective for its emotional autonomy. He viewed natural Pokémon as inferior, advocating absolute control over their perfected holographic counterparts. In his final bid for power, he unleashed mirage replicas of Entei, Articuno, and Zapdos to extend his influence beyond the lab’s confines.

Exposed by Professor Oak during the ensuing chaos, Dr. Yung shed his alias, proclaiming his intent to remake the Pokémon world. His downfall came when Mirage Mew self-destructed to destabilize the Mirage System, enabling Pikachu to obliterate Mirage Mewtwo. As his laboratory crumbled into flames, Dr. Yung vanished into the wreckage, evading authorities. His fate post-escape remains unknown, leaving his legacy as a cautionary tale of ambition warped by vengeance—a fallen researcher whose technological hubris underscored the peril of crossing ethical frontiers in pursuit of perfection.