The yinglets' enclave guards wear a very simple breastplate (looks like just a piece of thick leather and what seems like a padded headband.
Anything more would likely take away their one advantage (they're small and fast) while not being enough to provide meaningful protection considering how frail they are.
If Kass got geared up for war on Ivenmoth's dime, I'd guess the armorers would mainly look at layered cloth, maybe with stiff leather reinforcement over vital areas. Enough to keep a glancing hit from cutting all the way through an entire yinglet, because anything more ain't happening.
If the planet they're on has something comparable to earth silk, it's not entirely out of the question for someone sufficiently clever to come up with the layered silk cloth invented in the late 19th century, which was actually bulletproof (at least against blackpowder pistol rounds) and would probably be the absolute best protection a yinglet of wealth and status could ever wear.
The yinglets' enclave guards wear a very simple breastplate (looks like just a piece of thick leathe
