Azusa Matsudaira is the science officer and experimental biologist for the Terrestrial Administration Center (TAC), dedicated to combating supernatural Aragami threats. Her core duties involve researching, developing, and creating specialized biological weapons against these entities, keeping her primarily in the laboratory rather than field operations as she advances technological support for the team.

This intense professional commitment deeply affects her personal life. She is a divorced mother to her son, Matsudaira Jun, acknowledging her workaholic tendencies contributed to the marriage's end. Despite this, she maintains amicable relations with her ex-husband. Azusa views herself critically as a "bad wife and worse mother," though her ex-husband and son still hold affection for her. The demands of her TAC role restrict her custody time with Jun.

Personality-wise, she embodies a strong "For Science!" ethos, relentlessly prioritizing research and experimental solutions, sometimes to the point of exhaustion. She shares the intellectual role ("The Smart Guy") with colleague Yoshiki Yaegashi, depending on the scientific challenge. While caring for teammates like Momiji Fujimiya (the Kushinada maiden), her perspective remains distinctly analytical, focusing on studying their unique biological properties relevant to the Aragami conflict.

She originates from Nagoya, Japan. No specific physical characteristics like height or weight are detailed. She possesses no noted special abilities beyond her scientific expertise.

Azusa appears as a supporting character in the 1994 "BLUE SEED" TV series, the 1996 "BLUE SEED 2" OAV, and the "Blue Seed 1.5" OVA. Within the "Blue Seed 1.5 [Premium]" OVA retelling, her role remains consistent with her established functions in the main series.