Spren

Spren are creatures of nature. With the exception of Shinovar, where there are no spren, they have a common presence all over Roshar and tend to be ignored, or remain unseen. Spren are not fully understood. They take different shapes and forms, appearing around certain events, ideas, or abnormalities. Some types of spren have taken on cognitive ideals or concepts which have ,in turn, taken on literal personification over time.

Spren can be very elusive and even the most common types may refuse to appear. Spren are typically amorphous and often change in size, luminosity, and shape. Whether they actually manifest physically remains in question. Most Spren in Roshar doo not appear sentient and can not interact with the physical world. However, some variety of Spren, such as windspren, are capable of physical interaction and have a reputation for being tricksters.

Whilst many spren appear to do nothing but gather around whatever they are named after, some people think that the spren cause the things they're named after rather than the other way around. For instance, many believe that rotspren cause infection in a wound, as opposed to gathering as a sign that there is an infection present. Human perception has a lot to do with why spren act like they do.