I have an alt that I didn’t do much of the story/chapter quests with. I got my JC to Rank 4 for ring slot on an alt to make for a main. When I hover over the optional reagent slot, that will be used for the new vestige reagent, It says "Assist the Runecarver further to unlock this knowledge.". I cant fine anything about it other than saying the Maw quests.
Im 3/9 chapters in: Chains of Domination
2/9 in the covenant campaign chapters
3/7 in Secrets of the first ones(Not that this one matters but still)
Its strange because the runecarver is unlocked for me on this alt. The box of many things is unlocked. I cant see what im missing.