Minazuki-ka no Iinazuke: Juuroku-sai no Tanjoubi, Honke no Toushu ga Mukae ni Kimashita

The young girl Rikka Minazuki lost her father to a strange illness, leaving her all alone in the world. She has lost her reason for living, until a young man claiming to be the head of the Minazuki family appears before her and tells her the shocking truth.

"You and I are meant to be engaged to each other."

Rikka knew nothing about the arranged marriage until now. It turns out Rikka knew nothing about her father, the family code, nor the fact that the Minazuki family is the "descendant of the celestial maiden," as told in the legend of the robe of feathers.

(Source: Kodansha, translated)