ロックマンXシリーズ
Dr. Cain, a human archaeologist-turned-robot expert, serves a vital, yet shrinking role in the "Mega Man X" games and their backstories. In the story of "Mega Man X" (told in the form of Dr. Cain's journals), Dr. Cain discovers the dormant Mega Man X in the ruins of Dr. Light's lab. After awakening X, Cain invents Reploids, sapient robots based on X's design, with the most notable being Sigma. Sigma, being the most advanced robot at the time, was placed as the head of the Maverick Hunters (Irregular Hunters in the Japanese version), a group of reploids dedicated to destroying any reploid that violated the three rules of robotics.