There might be some skills that would need not only certain levels of proficiencies, but some Unique items. These items might be foraged, crafted, bought, stolen from other players or a combination of those.
For example:
Small game of the Lumber-wood hunting
"bla bla bla."
- bla
A skill that lets you to attack little creatures of the darkness. Requires a Unique inspirational (some body parts of a hide-behind, turkey feather, ink and a sketch-book (bought from stalls), maybe some other stuff).
Hide-behind body parts may be found in the darkness like indian feathers and arrowheads.