Tokiko Tsukuyomi

She was the minister of education, but she resigned a few days after Nasa and Tsukasa married. As for why she says she is worried about her health and she may no longer be involved in politics due to her age. She has great influence and power. Indeed, she easily tracks down Tsukasa's location while she was still living in Nasa's apartment. In chapter 70, when Nasa and Tsukasa go to a hot spring resort, she appeared in front of Nasa acting a little dramatic like she was lost because the resort was too big. When Nasa takes her back to her own room, Tsukasa appears and reveals her identity as her grandaunt.

(Source: Tonikaku Kawaii Wiki)