So I am stuck…
This is, in my opinion, quite retarded game design.
I don’t mind the inconvenience of having to return back to town to do the crafting (some will).
BUT it is stupid that, having cleared part 1 of the tunnel, you need an Invoker to activate part 2 AND the game can hard-wall you from progressing because they simply don’t give you the correct mat type to make the correct invoker type.
This is next-level dumb design.