Hierophant

Hierophant is a designation granted to mages that possess innate abilities deemed unreachable by magic. If a given hierophant's ability is considered by the Council to be of extreme value, they are offered a stipend in exchange for their continued services, development of their powers and the authorization for the Council to study such powers during life and even post mortem. Specifics are negotiated individually.
The Hierophant designation is thought of as an example of a Sword of Damocles, since the designated are treated by the Council with equal amounts reverence and aprehension. Reasons are aplenty, from the duty to preserve the Veil to the Council's desire to always keep hierophants within arm's reach in case they need to consult with them, potentially limiting their freedom as individuals.