Question: these beautiful spirits, could they be summoned at anytime with little to no cost? How long could the materialization be maintained?
This is for, research purposes.
@Mojo
While not nearly as thin as that, armor had thinner areas (commonly made of only leather, cloth, and/or even chain mail at times). It was used mainly around joints to allow for a wider range of movement and the ability to ride on horseback without too much resistance.
ShadowWalker
If I had to guess, to grow some kind of drug. That or to implant a vine seed under their skin on either their hand or foot and grow it rapidly (but still slow enough to not kill them or knock them unconscious from the fear and pain).