This Is My Mansion. Could You Leave Now?

Seventeen-year-old Marissa, the daughter of a marquis, has been planning revenge against her uncle’s family, who barged into her mansion and acted as if they owned the place after her parents passed away.
When she turns eighteen, her title will finally be returned to her…
Until that day comes, she has endured constant bullying at home and at school, all for the sake of enacting grand revenge on those who tormented her.
In the midst of this, her fiancé Deliol suddenly breaks off their engagement.
It turns out he is in love with Marissa’s uncle’s daughter—her stepsister Roxanne—and believes she is his destined partner.
Marissa, who never liked Deliol to begin with, gladly accepts the annulment.
“If it’s come to this, I’ll make sure he gets what he deserves along with my uncle’s entire family!”
So she swears in her heart.
But despite her strong will, Marissa’s body has grown frail from years of mistreatment.
Unable to look away from her condition, Raid, a classmate at the academy and the kingdom’s third prince, begins to support her after the engagement is broken…