Itsutsuko no Sofu

As the dedicated manager of the Toraiwa Hot Springs inn, this gentleman serves as the maternal grandfather to the Nakano quintuplets. He is also the father of Rena Nakano, maintaining a deep connection to the family's lineage. Through his role overseeing the family's traditional inn, he remains a pivotal figure in the lives of his five granddaughters, anchoring the family's history and their shared connection to their ancestral home.