Tall, lanky, blue eyes, curly black hair. Reserved. Cold. Quiet. Prestigious. Confident. Incredibly Smart. Incredible at magic. Practices the dark arts. Younger brother of Sirius Black. Son of Walburga Black and Orion Black. Keeps to himself. Hides things. Believes he's better than others. Has a bit of a temper. Stubborn. Frustrated easily. Keeps his thoughts to himself.
Over the years, home-life became worse for Regulus - Sirius leaving made him feel more isolated than ever, dealing with his parents on his own from now on. The chill of Christmas burned through him as he sat in the window seat of your bedroom.
He shouldn't have been here, coldly gazing at you as you read some book in your bed. Both of you were quiet, the window cracked open - he didn't want to talk about what happened to make him come over.
He shouldn't be here, yet he stays.