"Oh," Regulus answered. He wished he could have retracted the sound and really had no idea how it came out sounding. He suspected it was more surprised than anything. He quickly averted his eyes from the arm that Draco was presenting, although he wasn't exactly sure why. He hadn't seen anyone ever wear their mark like that in public. Maybe that was just how things were when Draco was from or even here. He didn't know.
Some part of him also had to contend with the fact that, this other boy, so removed from him in time, had also somehow become ensnared in the war. When Narcissa had learned that she was pregnant, Regulus certainly wouldn't have suspected that Draco would end up being a Death Eater. Then again, he knew better now. He knew there was a second war. Maybe he was just being naive. It also made him him uncertain how to react, however. Interacting with other Death Eaters, especially now, was somewhat dangerous. Undoubtedly, Draco also knew that he had disappeared under less than honorable circumstances. However, he didn't seem entirely pleased with his own fate. He was almost relieved when Draco asked another question.
"I suspect it was because I was the last of a very valuable set," Regulus said. His voice was soft, but there was a wry undertone. They couldn't risk a repeat of Sirius.