It was never a good thing when an Elric or someone closely associated to an Elric was asking about souls and soul energy. Envy was on one of his very infrequent trips into the Nexus (hey, New York City keeps him busy, and the twins keep him even busier) in his occasional quest to hunt down a certain necromancer/alchemist from another timeline when he saw a Riza at the sign.
Her question worried him a bit. Especially since once he looked at her again, he realized that was the one married to the apartment manager that Envy's younger brothers liked to keep an eye on.
"Magic's the wife's area," he answered, shoving his hands into his pockets. "But I know a few things about soul energy."