Series
In Season 6, Ghost Riders appear in Beacon Hills, California when the Wild Hunt comes and are stuck in the town. The Ghost Riders ride their spectral horses during the storms and erase many of the town's citizens from existence, including Stiles Stilinski.
One Ghost Rider, known as the Outlaw targets Scott's Pack and is captured by them, then is killed by Garrett Douglas. After Stiles' erasure from existence, his long-deceased mother Claudia Stilinski is now seemingly alive, a ghost rider having taken on her appearance after being conjured by Sheriff Noah Stilinski's memories.
Douglas is then transformed into a new Ghost Rider, taken to ride the Wild Hunt once they are freed and leave Beacon Hills.
Creation
A Ghost Rider is a former human or former supernatural being that has been taken by the Wild Hunt.
One becomes a Ghost Rider when multiple riders converge upon their victim, endorsing him or her to join the Wild Hunt forever. Garrett Douglas attempted to control the Hunt, but when the spectral riders came upon him, he became a ghost rider with his personality completely stripped.
When the ghost riders erase multiple victims and take the to the phantom train station limbo, the victims wait for the train to board and once they board the train, those victims will be transformed into Ghost Riders, and ride the Wild Hunt.
Personality
Powers and Supernatural Status
Erasure
The supernatural talent, reality erasure, is a ghost rider's unique ability to erase people from existence.