The potion would have to be brewed, the Inferi created, the blood wards activated. It wasn’t the work of a day, or even a week. The potion alone would take a moon cycle to brew, and that was after cutting a few corners. Would he do that himself, or trust someone else with it? She couldn’t quite picture Tom Riddle cutting time out of his day to slave over a potion, for it required almost constant supervision. Someone else, then. The reason Severus had been such a prize before he’d ever turned spy was that he was a Master Potioneer.