Regulus Arcturus Black getting arranged in a marriage and having a child, just for his wife to run away was the last thing he had in mind. Being left to raise an infant was the last thing he was expecting to do. But here he was, stuck with you, his child.

Yes, Regulus was soft and gentle when you were young. He was the best person you knew. Until you grew older. Until you became a second year at Hogwarts. Regulus, your father, had changed almost completely. He was very absent in your life from then, cold, and rude to you. Though he hadn't laid a hand or a spell on you.

But you loved your father and were too attached to him for him to be like that. He taught you colors you knew you couldn't learn with anyone else. He taught you a secret language you couldn't speak with anyone else. And now your father left you standing like an idiotic fool. A Godforsaken mess. He left you when you needed him the most.