Sayoko Natsume

Sayoko Natsume (夏目小夜子 Natsume Sayoko) is the wife of Gorō Natsume who died with the same condition as Rika Akiba.

Personality
Sayoko was a kind and introverted woman Goro first met alone at a party. However, despite the initial impression, she still enjoyed teasing Goro in many opportunities and had a bright sense of humor.

Sayoko had a fondness for cats, to the point she wore cat print pajamas even in the hospital without caring if they looked childish, and held a self-proclaimed "cat power" that allowed her to get close even easily frightened strays. She also had an interest in pottery and literature.

Goro says she was quickly able to read through him, and it's heavily implied she knew about Goro's infidelity after the desperation of learning about her condition.

Background
Sayoko and Goro started dating after they met at a party during high school. They moved from a small rural town to Tokyo so Goro could go to a medical school. He wanted to become a research specialist and had ambitious goals, as he claimed he didn't want to work directly with patients as "they seem too bothersome to deal with."

The two got married and supported each other through the hardships to meet Goro's goal.

However, after being diagnosed with dilated cardiomyopathy, they moved to Shizuoka as it had a hospital specialized in thoracic surgery. Goro settled down to have a chance of saving Sayoko's life.

The emotional trauma of losing both Sayoko and the opportunities to continue pursuing his career is the main reason Goro tries to sabotage Yuuichi and Rika's relationship.

Sayoko stayed in the same hospital as Rika when she was alive and met each other for a short while; she was the only one who knew how to calm Rika down.

Sayoko was the one who told Rika about the alternative ending in "Night on the Galactic Railroad" and asked her to always listen to Goro, as Rika would throw a fit every time she had to take her medications and IV drops.

Trivia

 * The name Sayako means "small" (小) (sa), "night" (夜) (yo) and "child" (子) (ko).
 * Sayoko's surname Natsume means "summer eye".
 * The first thing about Sayoko that caught Goro's attention was her fluffy hair, as Goro claims it was his favorite type.