Inside the Skill Pillars? (Spoilers Farseer and Tawny Man trilogies)

[solarus]

Or perhaps those who created the pillars.

Fool's Quest spoiler

In the prelude to Chapter 23 "Bonds and Ties" the creation of Skill pillars is discussed. It mentions how those who create the pillars give up "...years of health" and that it is "...dangerous and expensive to the spirits and physical health of those who do the work,"before going on to say that they will suffer a "...youthful dotage."

This sounds very much like what Verity experienced whilst carving his stone dragon, so it is possible that the "essences" of the creators exist within the pillars in the same way as Verity exists within the dragon.