Overview: The guardians of the Overworld, warriors who serve the Queen and the royal family.
Details: Sentinels come from all walks of life. Mythos, Lucid Dreamers, Dream Constructs, anyone who has the proper qualifications to represent the Overworld by defending it. Sentinels are all granted special gifts by the Queen herself, usually the ability to never need sleep at all and remain ever-awake and ever-aware. But, there is a price for this. They are bound to the Queen's will and will drop everything to attend to her should she call for them.
Sentinels rarely leave the Overworld. Those who do have specific missions they are attending to.