The multi-generational family depicted in Summers Wars. They gathered in order to attend the matriarch's birthday.
The Jinnouchi family is a matriarchal one, women have power. They have a long history whom they are proud of, even though they admit their ancestors were idiots, they descend of them. The family has a grudge with Wabisuke, apparently first for being illegitimate, then mostly for taking the most of the family's wealth and go to America. Sakae is the matriarch and she is loved by all, especially Wabisuke.
Jinnouchi Tokue married Sakae (89) with whom he had four children: Mansaku (68), Mansuke (70), Mariko (71) and Manzo. Mansaku had three sons: Katsuhiko (40), Kunihiko (42) and Yorihiko (45). Additionaly, Tokue had an affair and Wabisuke Jinnouchi (41) was born, and later adopted by Sakae. Mansuke had three children: Ikezawa Kyiomi (39), Miwa Naomi (42) and Jinnouchi Tasuke (45). Mariko had two: Riichi (41) and Rika (42), who is divorced. And Manzo had a daughter: Yukiko (47). Katsuhiko is maried to Yumi (38) and they have three children: Ryohei (17), Yuhei (7) and Kyohei (0). Kunihiko is married to Nana (32) and their daughter is Kana (2). Yorihiko is married to Noriko (37) and they have two children: Shingo (6) and Mao (9). Ikezawa Kiyomi is married, has a son, Kazuma (13), and is expecting a daughter. Tasuke has a son, Shota (21). And Yukiko is married to Kazuo (55) Shinohara and they are Natsuki's parents (18).
Sakae has a dog, Hayate.
The Jinnouchi family is represented as having a large diversity of occupations, from fisherman to agent of the government and firefighter. Some came handy when the situation arises.
Riichi is a member of Japan Ground Self-Defense Force and was able to get a super equipment to have a better internet connection to fight Love Machine.
Rika Jinnouchi works as an agent of the city's government.
Mansuke owns a local fish market and was able to get a boat to give electricity and ice to the super computer.
Tasuke works in an electric store which mainly deserves private and gets a huge super-computer to help.
Shota is a police officer, he arrests Kenji.
Kazuo, Natsuki's father, works for Tokyo's water department.
Kyiomi is a care worker.
Mansaku's three sons work for the Fire Department. Yorihiko is an Emergency Medical Technician, Kunihiko is fire sergeant and Katsuhiko is a firefighter.
Wabisuke is a professor in Carnegie Mellon University and the creator of Love Machine which he sold to the American Army. He is the only one to know how to stop it.
Mansaku seems to be a doctor, he monitors Sakae's health issues.
Sakae was apparently a teacher, and she has connections everywhere in the coutry. She calls all of them in order to have them work. Ryohei, while not working or taking an active role in the film, is playing a baseball match during the ordeal. The match parallels what is happening thorough Summer Wars and he ultimately wins, as his family survives the Arawashi crash landing and Love Machine is destroyed.
Hayata, Sakae's dog, is the one that alerts the family about Sakae's death. He is also seen barking at the Arawashi as it is going to fall on the family's house.
The whole family gathers for dinner and Natsuki presents them to Kenji, her "fiancé". They are surprised when he is revealed to be Oz' hacker, though it is not him. He apologizes for lying. They express surprise when they see he is back but are not aggressive toward him, except Shota, but that's because he does not want him near Natsuki.
They are joined by Wabisuke, whom only Natsuki seems happy to see. During the ordeal Yorihiko, Kunihiko, Katsuhiko and Kazuo are working, and having great difficulties. The three brothers are surprised to receive call from their grandmother at work, encouraging them. Sakae goes on an call very important members of the government to encourage them to work finding a solution, her determination touches Kenji who begins to work and eventually opens Oz to everyone. The family celebrates but Kazuma says it is not the end. Wabisuke admits he created Love Machine and goes away when Sakae is angry at him. Newt morning, Sakae is found dead, due to the hacking of Oz, Mansaku was unable to have the notice and could not intervene in time.
They deeply mourned Sakae when she died. While the women went to oversee the funerals, the men decided to fight back and lure Love Machine in a trap. The women were not happy with it, the younger children just wanted to play. Tasuke provides a super-computer, Riichi a special operation vehicule to use as connection and Mansuke a ship to produce electricity and it also has ice to cool down the computer. Kazuma sends a defi to Love Machine and is able to trick him into the castle, the trap they elaborated with Takashi Sakuma. However Shota was left out of the plan, resulting in him taking the ice from the super-computer's room to preserve Sakae's body. It causes the attempt to capture Love Machine to fail. Angered, Kazuma strikes at Shota.
It is then revealed that Love Machine has set Arawashi to crash land on a nuclear plant. This made everyone realize how dire is the situation. King Kazma having been beaten Kazuma break down crying as he cannot protect his mother. They all admit they need Wabisuke to stop the virus. After reading Sakae's words of encouragement and Wabisuke's arrival, they have a feast.
They all give their avatars to Natsuki so she can play against Love Machine to retrieve the account with Arawashi's guidance codes. When she has troubles, people all around the world give her their avatars and she defeats Love Machine. Except it still has two accounts, Kenji's and the Arawashi's, and that it has set the later to crash land on their house. They immediately catch children and dog, ready to leave, until they remark Kenji has not given up. They stay with him and see Love Machine destroyed by Kazuma, as Wabisuke destroyed its defense and Kenji accesses the guiding of the Arawashi. They gather to protect the children as Arawashi crash lands right before the house, causing a lot of damages. They all make it alive.
At Sakae's fuberals, the family apparently decides to also celebrate her birthday, much to the crowd's surprise, even Sakae's picture is laughing. They also express the desire for Kenji and Natsuki to really date each other, as they seem to consider him part of the family, only Shota disagrees and he is promtly driven away.
- When Natsuki presented her family to Kenji, he outright said he was not sure he could remember all of it.
- Some members never appear.