My House Became Independent Because It Was Said to Be Useless!

Yakutatazu to Iwareta node, Watashi no Ie wa Dokuritsu Shimasu!
役立たずと言われたので、わたしの家は独立します!

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My House Became Independent Because It Was Said to Be Useless!
Yakutatazu to Iwareta node, Watashi no Ie wa Dokuritsu Shimasu!: Densetsu no Ryuu wo Mezame Sasetara, Naze ka Saikyou no Kuni ni Natteimashita· 役立たずと言われたので、わたしの家は独立します!~伝説の竜を目覚めさせたら、なぜか最強の国になっていました~
novel

Flora, the daughter of the western frontiers Margrave, came back from the battlefield to find out that her fiancé wishes to annul their engagement. It didn't really matter to her, but what did that foolish prince mean by "a worthless nobody of the Margrave's family on the edge of civilization"? And while there are signs of a conspiracy in court, even worse news about the invasion of demons arrives from the territory. The advance of the saint, who is loved by the legendary dragon and the fluffy spirits, has finally begun! (Source: Kadokawa, translated)