Hanaoka, the elderly butler of the Nikaidō family, has provided continuous service for over 45 years. He maintains a calm and gentle demeanor. His central responsibility involves caring for Harunobu Nikaidō, whom he has attended since Harunobu's infancy. Hanaoka exhibits deep devotion to Harunobu's well-being, particularly regarding his chronic health issues and shogi match outcomes. He demonstrates extreme indulgence toward Harunobu, sometimes excessively, including secretly tracking Harunobu's movements via GPS without his knowledge as an expression of protectiveness. Hanaoka shows a fondness for pastries from Mikazukidō, especially their signature "Mikazuki-yaki" treat. His narrative role consistently centers on his duties as Harunobu's caretaker and butler.