I just finished The Alloy of Law by Brandon Sanderson. As is the norm in many of Sanderson's Cosmere books, the story is followed by a short section titled "Ars Arcanum," with a description of some of the various kinds of magic present on that particular world of the Cosmere. (There's a bit about the naming of this section on Sanderson's blog, here.)
While lazily skimming that section, I noticed that the final sentences read:
It is primarily concerned with things of the Spiritual realm, and is of the greatest interest to me. If one of these three arts is of great interest to the Cosmere, it is this one. I think there are great possibilities for its use.1
Most of the rest of that section was written neutrally, without a specific voice; however, those lines reveal that someone must be speaking. Those last few lines force the weary reader to wake up and pay closer attention to that which he has just read. (At least, that was the effect it had on me.)
Who wrote those lines? Is is Mr. Sanderson himself? Is it Hoid, the world-hopping character who finds himself in many of the Cosmere stories? Is it someone from Scadrial (the world of Mistborn, and The Alloy of Law), or elsewhere in the Cosmere?
(Note: there may be clues in Arcanum Unbounded, but I have yet to read that collection.)
1 I am uncertain of the author's intention, but I feel uneasy about whoever it was that wrote this. I understand that the art described, Hemalurgy, was just described in that appendix as "not evil," but is known only (to me, at this time, at any rate) as an art that requires very bloody (described as "messy" in one of the books) murder and implanted metal spikes to function. I would feel uneasy about any character that found Hemalurgy interesting. (At least, more interesting than Feruchemy or Allomancy. Those are clean magics, and feel a lot more fun and wholesome.)