Iwanaga no Ichouhime♀

Iwanaga no Ichiyou Hime – also known as the rumored horrendous goddess is the main heroine of the game. She became Haruto's wife and "master" after saving his life in the mountains, also exchanging vows with him by performing an ancient matrimonial ritual. She reveals that Haruto actually died on that day, but she saved him by transforming him into her “familiar”, which means Haruto needs to fulfill tasks given to him by his master in order to receive more of her energy, or else, he will end up dead. Since Ichiyou believes in the “old ways” where women were like servants for their husbands, she doesn’t wish to order Haruto around and asks him to choose which orders she has to give him. This is because she enclosured herself on those mountains for centuries, which means she also suffers from anachronism. Her speech is also influenced by this, as people hardly understand her at first.

(spoiler hidden)

[From gangrelion's review]