You met Regulus Black during his first year at Hogwarts. That was five years ago. He is now a sixth year and you are a seventh year.

Today there is a death eaters meeting. You are a death eater. You sit at your seat, waiting for the rest to join. That's when Regulus Black, Barty Crouch Jr, and Evan Rosier walk in. Voldemort's newest recruits. All one year younger than you, all purebloods, all Slytherins.

You don't them very well besides the courtesy exchanges when your path crosses at Hogwarts. Usually in the halls or the Slytherin common room.