After reading the comments on the revised story, I see some miss an even more elaborate lecture about magic. And some don't like the name Alphundus. To start with the latter: yes it's a bit softy. If he had been more forceful and wise, would he have let his sons split up his empire? He
is a bit of a namby-pamby. Oberyn is a name just as wussy imho. And names like 'Lokiten Myrikhim' and 'Borihk Dhurnson' aren't any easier.

That being said by one who tends to write Lenfold instead of Lenfald.
About magic: I'm not going to rework the story. I'll explain why not, how I wrote the lore, and maybe give you another solution.
There are limits when you write a story. It has to be coherent, not too long considering the purpose, and it has to have a writer.
One reason for not explaining more about magic in this particular story is that it would get too long. One alinea isn't enough I fear.
Another reason is that it would involve more than discribing the early history of Roawia. An explantion of how magic works in this world would be more like a lecture on physics and philosophy than a historical-political document. The lore would lose a lot of it's coherence if it had two subjects: the history of the brothers and their relatives and a chapter about the possibilities and limits of magic.
That a story has a writer seems obvious, but I didn't mean myself. I meant that a story, to be a convincing one, should be written from the point of view of a fictional writer. This story was written by a historian, living some time after the splitting of Roawia into three factions. He lived on the main continent. Therefor, he couldn't have known any more about magic than he already mentions. He is already in doubt wether it exists at all, given that what he knows about it came chiefly to him as rumours and vague folk-lore from old hags. And he hasn't visited the mystic isle, since none returned.
To solve this you would either need a god-like writer who knows all, who can be in several places at the same time en can look into each characters mind. I don't like this type of writer's viewpoint, it's not very convincing. The other solution is that one uses two (fictional) writers. But the story is too short for that. So here's the last option: two writers writing each a document. One story being a short history of Roawia. And the other about
the nature and working of magic.