22 years old, the eldest daughter of the Shinohara family. She is the great-granddaughter of Sakae Jinnouchi. A girl who was the school idol and a member of the kendo club, she is Kenji's senior. Bright, active, and friendly, she is the picture-perfect 'school idol,' though her grandmother Sakae described her as having a 'childish and selfish side.' Due to her beauty, which resembles a young Sakae, many boys admire her. Kenji is one of them. She respects her great-grandmother Sakae and adored Wabisuke, her half-great-uncle (her maternal grandfather's half-brother).

21 years old, a third-year student at Kuonji High School in Tokyo. A member of the physics club, he is a quiet and somewhat timid 'science boy.' He is gifted at mathematics, to the point of being a genius, and competed in the Japanese representative selection for the Math Olympiad, though he lost. He quietly regrets that defeat. A year ago, he came to the Jinnouchi house as Natsuki's fake boyfriend. After everything that happened, they eventually started dating, and he has ended up coming to the Jinnouchi family gathering again this year.

16 years old. A first-year high school student and one of Sakae's great-grandchildren. While the relatives gather, he stays alone in the storage room working on his computer. At first glance, he looks like a gloomy computer geek, but he is actually a master of fighting games who controls 'King Kazma,' a tall rabbit-type avatar and the world champion of OZ's fighting games. He is a big-name super player with global corporations as sponsors. Cool, somewhat blunt, and composed, he seems to take considerable pride in his avatar being the champion, placing more importance on winning the fight than the game itself. While his playstyle is calm, he can lose himself when he gets fired up. He has a history of being severely bullied and learned Shorinji Kempo from his grandfather Mansuke via OZ, so he calls Mansuke 'Master.'

A spirited 9-year-old girl. A prankster.

A spirited 6-year-old boy (with dyed blonde hair). A prankster.

A spirited 7-year-old boy (wearing glasses). A prankster.

42 years old. Single. The illegitimate child of Tokuei Jinnouchi, who was an adopted son-in-law. He was taken in by the Jinnouchi family at a young age and became Sakae's adopted son. He hadn't returned home for over 10 years until last year. His nihilistic behavior stands out. Despite appearances, he is highly educated, having graduated from the University of Tokyo and studied abroad in the United States. He has a streak of irresponsibility. Put kindly, he is pure; put harshly, he is childish. Slender and tall. A handsome older man. He is likely quite popular with women.