Hiroshi Kishida, a visionary scientist, co-founded the clandestine organization MET with Dr. Mishina to exploit three radiant shooting stars—crimson, azure, and emerald—left among seven celestial entities that crashed to Earth with colossal energy reserves. Together, they pioneered the "Musumet" helmets, advanced devices engineered to magnify users’ physical prowess and latent abilities, aiming to deploy this technology for global security and neutralize dangers from the four uncharted stars.

After the tragic demise of Dr. Mishina and his spouse, their trio of daughters inherited the Musumet mantle to pursue their fathers’ vision. Though Kishida’s direct engagement with MET post-transition is ambiguous, the organization’s operational framework implies his enduring influence in advancing its goals. His scientific innovations and alliance with Mishina formed the cornerstone of the Musumet initiative, merging tactical planetary defense with the delicate equilibrium of its adolescent protagonists’ heroic and civilian identities.