- Seiya's son is Hokuto Hidaka, and his wife is a famous actress.
- Seiya is very affectionate towards Hokuto, but Hokuto can't stand being around him and has snapped at him on multiple occasions.
|Character||Seiya's Nickname||Nickname for them|
Hokuto's grandmother, who is not part of the entertainment industry. Although Hokuto lived with his parents, they were busy with their entertainment work, so Hokuto's care was left to his grandmother. While Hokuto often feels pressured to follow in his parents' footsteps and please them, his grandmother always encourages Hokuto to follow his own path. As a result, he is much more closer to her than he is to his parents.
Hokuto lives by and quotes his Grandma's words semi-regularly. He loves his grandmother dearly, and many of his tastes, including his love for konpeito, are likely shaped by hers, leading to him often being called old-fashioned.
- Hokuto's grandmother attended the DDD to support Hokuto, but Wataru helped escort her out during the semifinals because the noise was too exhausting for her at her age.
- Wataru met her during a seminar on haiku, and she invites Wataru out for tea where they chat. She and Wataru have exchanged e-mail addresses and presumably communicate often as well.
- Hokuto's love for konpeito originates from his grandmother, who would often give it to him.
- Hokuto trusts his grandmother completely and lives by her words of advice.
- Whenever Makoto hears Hokuto's stories about his grandma, he is often moved to the point where he is in tears.