Naoko Kurusu

Naoko Kurusu is Keigo Kurusu's wife. Yuki and Yuno are welcomed by her at the bridal fair and she acted as their guide during the whole day.

Yuki and Yuno coincidentally spot Kurusu's wife, who they met previously at a bridal fair, on her way to visit Yoi in hospital. The pair are caught by Minene but Yuki accidentally sets off bombs which alerts Kurusu to their location. Kurusu calls Minene and threatens to kill her unless she co-operates, promptiny Minene to abandon Kurusu and form a new alliance with Yuki and Yuno, capturing his wife and son as her trump card.

(Source: Future Diary Wikia)