I always wondered where forgies came from?? Perhaps there is a forge stone forge somewhere!!?? With the correct ingrediants, perhaps a number of tome's placed about the Blackstone area hold the key. But the fogre or forge's are located in very dangerous areas. I'd suggest that Shally's liar has the higher tier forge stone forge and can be only used when you banish him (he drops a key), and only once per player who was there when he was banished and only once per reset. Place lower tier forges, perhaps only one, in maybe the Bloodcult or else where that requires a party to enter. An added incentive to take on Shally or the Bloodcult. The alternative is to farm monsters which can be boring.
Sauce for the goose ...