Members of the Royal House can change their hair color or cause their hair to grow quickly at will. Normally the color of the Royal Locks reflects the person's emotional state by default but this can be controlled through training and discipline. The ability to grow hair at will takes effort and leads to hunger and exhaustion.
Only members of the Royal House that are potential heirs to the throne have and can pass on the Royal Locks. 
Hair Color Indicators
- Calm or control 
- Anger or embarrassment 
- Happiness or excitement 
- Fear or panic 
- Saddened or upset 
Wearers of the Royal Locks can imitate the grey hair of the elderly, though it is unknown whether that color is associated with a particular emotion.
Below is a list of those known to have the Royal Locks:
Vasher suggests that all Returned can alter their appearance to an extent, and points to the Royal Locks as evidence that the Royals are descended from a Returned. This indicates that all Returned could potentially mimic the effects of the Royal Locks. On the other hand, it has been revealed that Denth has the Royal Locks independent of his being Returned.
|Characters||Vasher · Vivenna · Siri · Lightsong · Denth · Susebron · Llarimar · Bluefingers · Blushweaver · Nightblood|
|Places||Hallandren · T'Telir · Idris · Kuth · Huth · Tedradel · Court of Gods|
|Magic||Awakening · BioChromatic Breath · Command · Drab · Heightening· Ichor-alcohol · Lifeless · Returned|
|Mythology and Lore||Endowment · Austrism · Five Scholars · Iridescent Tones · Manywar · Kalad's Phantoms|