"So the castle is acting like a forth year with a first crush. Splendid. Good to know" he said, sarcastically. "I guess the castle felt lonely enough to bring us from different time periods."
Regulus nodded. "Ah, that will go down in history as the day of the Battle of Hogwarts, according to the textbooks. The day the Dark Lord dies," he said. "Incidentally, the day you die and Potter turns you into a hero," he continued, because it was better if Severus learned it from him and not Sirius. "Apparently Potter managed to get all the horcruxes, and the only people who know about them are me and you, Potter and his mate Ron Weasley. He hasn't said anything to anyone. Ron actually told me, because they found out that I was trying to destroy them."
He shook his head, but smiled. "Sure, be smug about it, but I'll take access to the portraits. It'll be nice to speak to my great-great-grandfather."