So Shadow Lairs are kinda in a bad place right now, one of the main reasons is the price of the Shadow Key, I have an idea. How about we add 4 new Shadow Keys, one for each of the Boss Lairs. These specific shadow keys will only be able to open that boss lair. How to obtain them you might ask? Simple, you get them from brinks: The keys will come unbound.
Gloaming Wildwoods Shadow Key: 30 Frumious Fangs
Royal Jelly Palace Shadow Key: 30 Jelly Gems
Ironclaw Munitions Factory Shadow Key: 30 Bark Modules
Firestorm Citadel Shadow Key: 40 Almirian Seals.