NotEvilAtAll

they werent the first sons, that was confirmed by the creation lore post. They were the first of their kinds to organize and becoming prominent however, essentially they became the first to civilize their tribes which is why they are hailed as the fathers of their races. Just as a lot of rulers in recent history have attempted to recreate or imitate the roman empire. or in this case an individual like Caesar 

https://wikia.lordofthecraft.net/index.php?title=Ancient_History

I suspect you haven’t read this, which I clearly mentioned in what I said. The Wandering Wizard lore has been part of LotC since 2011, though who is to say it is true and not just fiction.

Edit: I’ll also just mention that the creation lore is vague enough to the point that it doesn’t say if the Four Brothers are the first or just random brothers who rose in power. That is the purpose of being vague, to add mystery.

im fairly sure it directly states that they were four brothers who became prominent.