The Brinarr (pronounced BRINE-ar) are entities made up of multiple Einarr souls inhabiting a coral-laced armor body.
The first successful Brinarr was Tessellation, followed shortly thereafter by Ampersand Five. Brinarr need regular submersion in water to remain functional; else their coral dries out and their constituent spirits can no longer interact with their bodies. Modern Brinarr armor can usually store Ethersea water in circulation for some time, but showers or submersions are still necessary to replenish those stores.
It has been established that Brinarr possess many human-like physiological responses. Rather than sweat, Brinarr exude a slime[1], and are still capable of smelling scents, despite not strictly speaking having a nose.[2] When traveling through water, Brinarr are able to propel themselves by jettisoning air and water through the hollows of their body, similar to how real-world corals and sponges can produce oxygen and pump water.
When injured, Brinarr bleach rather than bleed, slowly growing paler and paler as their coral goes into shock. Brinarr "sleep" by laying down in tub-like bodies of Ethersea water, a time which Zoox says is useful for relaxation and introspection.[3]
See Reefers for information on the bleached Brinarr drones.