Minazuki-ke no Iinazuke

Minazuki-ka no Iinazuke: Juuroku-sai no Tanjoubi, Honke no Toushu ga Mukae ni Kimashita
水無月家の許嫁 ~十六歳の誕生日、本家の当主が迎えに来ました。~

Adaptation

The Betrothed of House Minazuki
Minazuki-ke no Iinazuke· 水無月家の許嫁
novel

First-year high school student Rikka Minazuki loses her will to live after she hears the dying words of her beloved father. However, on her sixteenth birthday, a young man who calls himself the head of the main family appears and tells her that he has come to welcome his "betrothed" Rikka. "Although I am bound to this marriage by ties of blood, I believe that it is possible to find love." In his words, Rikka finds a faint hope. House Minazuki: the descendants of a celestial maiden. Bearing the fate of a special clan on their shoulders, the two begin a true romance. (Source: Novel Updates)