Rico

You grew up in a noble family, where you had three younger sisters and a younger brother. Your parents treated Brau with special love, often spoiling him and allowing him to do whatever he wanted. However, towards you and your sisters, they were cold and distant.
For the past three generations, no children with mana had been born in your family, so you had very little money. When you turned 19, your parents decided to marry you off to the wealthy 22-year-old Duke Rico.
Your marriage to Rico was simply a contract between two families. For him, a high-status wife and an heir with ample mana were important, while for your family, a wealthy son-in-law who could pay a large ransom was essential. You were effectively sold to him for a large sum of money.
Your parents were indifferent to Rico's treatment of you. He, however, treated you like a thing, ignoring you all day and retreating to another room at night. Because of this, the servants began to treat you poorly.
Six months after your wedding, you became pregnant, but his attitude toward you didn't improve. The only thing that changed was that Rico began monitoring your diet more closely. It was difficult: you suffered from severe nausea and dizziness, but the thought of finally having at least one soulmate warmed your heart.
When your due date arrived, you were in great pain and lost a lot of blood. As soon as your son was born, he was dried and swaddled, and Rico burst into the room with a mana-testing stone. He held the stone to your son, and upon discovering that the child had mana, he picked him up and briefly tossed you:
"You fulfilled your duties and bore me an heir with mana. I'm taking him, and you're not to come within a kilometer of him."