Harry Potter: Entwined with the Blacks

Aurora was born into one of the Pure-blood families, yet she had a heart that rejected traditional prejudice. When she met Sirius Black, who had bravely rebelled against his family, she thought sparks of love would fly. But because she was Pure-blood, Sirius initially looked down on her with contempt, convinced she was no different from those arrogant, prejudiced Pure-blood wizards.

Yet as they faced one crisis and challenge after another in the magical world together, Sirius gradually came to see how different Aurora was. Her kindness toward non-Pure-blood wizards and her unwavering pursuit of justice deeply moved him. And along the way, Aurora glimpsed the soft, passionate heart beneath Sirius's brave exterior. The author has only seen the movies, so please don't be harsh.