Fujiko Tsukuba (筑波不二子) is a Japanese biologist and coroner working in Tokyo. Born in Yokohama in 1965, she studied human and creature biology during her early twenties. She was 32 years old during the documented 1997 Seedian Invasion. Professionally, Tsukuba served as lead researcher and examiner of Seedian genetic structure during that event. A workaholic, she consistently arrived first at laboratories or morgues and left last, occasionally remaining on-site for continuous one-to-two-week periods.

Personally, Tsukuba identifies as lesbian. She exhibits flirtatious behavior toward an individual called Ms. Suzuka, entertaining romantic and lustful fantasies about her. Her personality features sarcastic and condescending tendencies, though she maintains professional conduct when the situation requires it.