Seita's Cousin is a character in Grave of the Fireflies. She is seen twice through the film and is mentioned by her mother.
Very little is known about her except that, unlike Seita, she went to school and resumed her normal activities during the war. She is seen having dinner with her parents while her mother complains to her and her father about Seita and Setsuko's behavior. She sides with mother and asks if she scolded her cousins.
It is unknown what happened to her after the war ended, except that she survived.
- Seita's Aunt (mother)
- Kiyoshi Yokokawa (deceased uncle)
- Mrs. Yokokawa (deceased aunt)
- Seita Yokokawa (deceased cousin)
- Setsuko Yokokawa (deceased cousin)
- Like her mother, her first name was never revealed.