Two Years Later
Severus and Marvolo got married the day before Halloween 1979, with only their closest family and friends in attendance. Following the wedding, after learning that Severus was pregnant, the couple headed over to Gringotts with a goal in mind.
One of the goblin account managers glanced at them and grinned a shark like grin before leading them to a private room. "May your enemies' blood bathe your blade. Well, Lord Slytherin-Peverell, Lord Ravenclaw-Prince-Pendragon-Emyrs. I'm glad to see that you've decided to visit us. What can Gringotts do for you?"
Severus stated, "And may your vaults overflow with gold. We want to start a family of our own, if that is possible, Master Razortooth."
Razortooth looked thoughtful before answering. "It is possible. Did you have a last name picked out?"
Marvolo brought an arm around Severus's waist and said, "Prince-Slytherin."
It made perfect sense, and together, they owned 3/4 of Hogwarts. They chose a manor in Northeastern Ireland and made it both unplottable and impervious to attack with the Goblin King as their secret keeper.
Severus then Apparated to Diagon Alley to shop for the baby, before meeting up with Marvolo.