It has its own set of history and rules that would be "logical" to the characters we play.
it is rather common principle in fantasy world that if you want to control power in some way, it is eighter temporary (one battle at most or less) or it need physical item capable of keeping the energy. <----- This is even valid for real world
You can never have the good sides of both as one and it is what you are trying to do. If I were you, i wouldn't base my ideas too much about the tiny amount of setting you find somewhere. Because it may be eighter old and not valid anymore after some thoughts or valid, but wrongly understood. And adding to this, when you are modificating this, you will most likely come with something what lacks logic.
It has its own set of history and rules that would be "logical" to the characters we play.
This logic.
Logic is always the same. While today we know more facts to base on, much more things are logical to us, than once. But in PS world, where people think like 500 years ago, but will magic, what is logical to us, wouldn't be always logical to them. Like magic is logical to mages, but none in RL.
If we knew everything, the logic would lead us always to truth absolute, but since there is infinite amount of secrets ahead of us, we will never be always right.
So no, you won't forge weapon of pure energy, which last forever, like normal weapons.
A city is built by people who have never seen Oja or Hydlaa. Do they nesicarrily name everything or know everything the same as we from Hydlaa do? No.
you need to read the setting and seriously think about it before you start making a guild. Yliakum is too small for people to never hear about Hydlaa or Ojaveda. Maybe not be there, but everybody in Yliakum speak in similiar manner.
Its possible to believe that while of course the city would know of people like Laanx and Talad they might not be familuar to all that we are.
Priests of Laanx and Talad would make sure everyone knows about their gods. Agaian, Yliakum is too small.