Grandmother Takasato is the grandmother of Kaname and mother to Mr. Takasato. She had a very hard time accepting Kaname, believing the child was stubborn. She would blame Mrs. Takasato for failing to discipline her elder son, though Kaname's younger brother Suguru suggests her dislike of Kaname was the result of how Kaname swatted their grandmother's hand away when she tried to pat him on the head during their first meeting.
She continued to be very hard on Kaname and began to favour Suguru, who was much more compliant. On the night that Kaname is spirited away, Grandmother Takasato insisted on punishing Kaname by having him stand outside the house on a snowy evening for spilling some water and not cleaning it up. She was unaware that Suguru had been responsible for spilling the water and allowed Kaname to take the blame as he had been afraid of his grandmother's reaction and because he enjoyed his grandmother's favouritism. While Kaname is standing outside, Grandmother Takasato argues with Kaname's mother about how to discipline Kaname, whom Grandmother Takasato intuitively senses is not like other ordinary children.
She passes away nearly a year after Kaname was "spirited away" to the Twelve Kingdoms.