I Belong to House Castielo

Sold off by her own mother, a young girl winds up in the house of the empire's most feared duke, Ein Castielo. Given the name Estelle, she must come to terms with her family, demon-lineage, and new standing in high society. But what will happen to the innocent Estelle when the enemies of the duke learn of her existence? Does she really have what it takes to be a child of the great and powerful Castielos?