I recently re-read the Cradle series up until this point. It's one of my favorite ongoing fantasy series right now.
One thing that bothered me slightly on my first read-through and immensely on my second read-through is how the Heaven's Glory school in Sacred Valley were able to poison and kill a Sage. Will said himself that the Sword Sage was two levels above Underlord, and I can't imagine even an Underlord getting poisoned by them.
I wonder if it was just an issue of planning and Will not thinking that he would make the power levels so extreme in the future, but that point just always stuck me as bizarre.
Hey OP! I know it looks like power creep getting out of hand, but this actually isn't a mistake! Weirdly enough. Usually if I do something that looks like a mistake, it is in fact a mistake.
In this case, I know exactly what happened to the Sword Sage and how he was killed, but (back when I was writing Unsouled) I didn't realize how obviously out-of-place this would become to the reader in a couple of books. If I had, I would have made it clear in Book 1 that it should have been impossible for mere Jades to do this.
The reason why I didn't comment on it initially is because none of the POV characters know how weird it was. They just know that a Sage is a big, powerful guy from other lands, they don't know exactly how strong he is or what that means. Even Yerin isn't really sure how much stronger he is than they are, because she doesn't know enough about the sacred arts yet.
I wanted the reader to notice that they shouldn't have been able to kill the Sword Sage, but in a "Hmm, I wonder how they did that?" sort of way, not in a "Wait a second, this is physically impossible" sort of way. Even though under normal circumstances, it is literally impossible. I just didn't realize how quickly and how clearly people would pick up on that in the next couple of books.
So anyway, TL;DR - the mystery has an answer, it is an answer I have planned out from the very beginning, and that answer will be revealed in the series. Also, I regret not making it clear in the first book that this was an intentional mystery and not a mistake.
P.S. I'm probably going to include the Sword Sage's death scene in a Presence Report, just not in Underlord.
"Even Yerin isn't really sure how much stronger he is than they are, because she doesn't know enough about the sacred arts yet."
Seems she's quickly come round though, since she referred to Eithan as a 'mere underlord' compared to her Master in the very next book.
She can know the names of the ranks and which ones are higher without knowing what that means in practical terms.
She isn’t sure HOW MUCH stronger he is than they are, “they” in this case including Eithan. But she knows he’s stronger.