Dr. Sakezō Sado serves as the chief medical officer aboard the space battleship Yamato, a role he assumed under unusual circumstances. Before Earth was devastated by alien attacks, he was trained and worked as a veterinarian, but the collapse of human society and the critical need for medical professionals led him to transition to human medicine, reinventing himself as the ship's surgeon. His given name contains the same kanji as the word for sake brewing, a detail that reflects his most prominent personal trait.

In terms of personality, Dr. Sado is a study in contrasts, which makes him one of the more distinctive members of the crew. On the surface, he is a carefree and often humorous figure, providing consistent comic relief through his deep and abiding love of sake, a Japanese rice wine. These moments of levity are often visual gags, such as when he secures his sake bottle in a safety harness during the ship's warp transit while neglecting to fasten his own seatbelt, or when he treats the bottle as a valued companion during high-stress operations. However, this lighthearted and frequently inebriated demeanor masks a profound dedication and a deadly earnest nature when it comes to his professional responsibilities. He understands the limits of medicine and the impermanence of life better than most, and he can become stern and authoritative when chiding crew members for irresponsible behavior or health-related negligence.

Dr. Sado's primary motivation is the preservation of life aboard the Yamato. His role in the story is twofold: he is both the essential medical authority responsible for the crew's physical well-being and a source of unconventional wisdom and support. His medical expertise is top-notch, and he is known to advocate decisively for necessary surgical interventions even when facing resistance, most notably in the case of Captain Okita, whose old injuries required critical surgery. Beyond emergency medicine, he shows a unique understanding of crew morale, such as when he quietly offers a room in the medical section as a place for new recruits to relax, demonstrating a compassionate and unorthodox approach to his duties. Despite his typical good humor, he possesses hidden depths and unexpected competencies, including the ability to act decisively in non-medical crises, such as disarming mutineers.

Key relationships define his interactions with the command structure. He enjoys a unique privilege in being able to speak openly and candidly with Captain Okita, a freedom few others share, which allows him to passionately argue for the captain's medical treatment. His connection to the series extends beyond a single character; Dr. Sado is a recurring archetype, or stock character, in the works of creator Leiji Matsumoto, with similar versions of the character appearing in other series like Danguard Ace and as an influence on Dr. Zero from Captain Harlock. Over the course of the series, his character remains fundamentally consistent, balancing his dual role as a source of humor and a vital operational asset. Information on his specific development arc in Star Blazers: The Comet Empire is limited, though it is noted that following the reorganization of the 65th Escort Squadron, he no longer appears to be serving in the fleet. In terms of abilities, aside from being an all-around top-notch physician and surgeon, Dr. Sado holds a military rank equivalent to a Lieutenant Colonel, which is comparable to that of a commanding officer, reflecting the high regard for his technical knowledge and medical expertise.