Mistra, changes radically depending on what adventure Elminster is having this week, so idk. Probably the lore impact would be she'd eventually give it o him and he'd have a wacky adventure with it? maybe involving time travel back to the time it was made and it turning up Elmy was the one who brough Netheril down or something? have they done that yet? I gave up with his series a long time ago.
