The article Eldritch Keystone: Tlhutlh is still unfinished and may be lacking detailed general information, screenshots, and crafting recipes. Please expand the article and remove the {{unfinished}} tag once the article can be considered complete.
Eldritch Keystone: Tlhutlh contains information about the ThaumCraft mod.
This mechanism looks like it would fit into the slots you have found in the monolith chamber walls. It is crackling with energy and seems ready to perform whatever task it was designed for.
When used on the indentations in the four walls of the chamber under the monolith, it reveals rooms with monoliths and possibly advanced items in a Void Chest.
