Hiya 
TL;DR need a chest/head component that is aether resist + bonus damage vs aetherials to compliment the sacred skull. 
There;s a component that goes into head and chest armors called sacred skull that gives resist to chaos and vitality, and increased damage to chthonians.
However, I had a look through all the components I’ve got and the blueprints I’ve got at the blacksmith but couldn’t see a component equal and opposite for it.
eg, no component for head and chest that gives aether resist and bonus damage to aetherials.
The precedent is set with Black tallow and aether soul, and purified salt and enchanted silver (or whatever its called).
thanks for reading