Honorspren

Honorspren are a type of sapient spren capable of forming a Nahel Bond. They are Splinters of Honor. Bonding with one makes someone a Knight Radiant of the Order of Windrunners.

In the Physical Realm, honorspren look like windspren. They can change their appearance, including forms like fire or clouds, although they always glow, and are always white-blue. This being said, they generally seem to prefer a humanoid form. Usually, it's very small -- only about a handspan tall -- but if need be, a honorspren can make themselves as tall as a regular person. The more powerful their bond becomes, the more they can change themselves, even being able to shift the color of their clothes if not their skin. 

In Shadesmar, honorspren are blue-white and as large as humans. They cannot vanish, or shape-shift. They appear to be wearing clothes, but the clothes are part of their essence and cannot be changed without Stormlight. Some honorspren buy physical clothes to wear instead.