Light Priests also known as Fosamancers & mantresses respectively are a class of mages who wield Light Magic as the energy source for their magical abilities. the use of said magic alongside Arcane Magic are the most common practiced across the titan universe.
Light Priests are commonplace around religious organization, particular those which worship the Eternal One Celestris, the patron deity of light. Light Priests use this magic to heal the ill & wounded and dyeing, the magic is also dangerous to those who's magic is aligned with evil intentions, such as Chaos Magic & Death Magic. Which is why the Templar Brotherhood were a key figure in most of their major dealings with the Covenant of Shen'dow, a prominent Death Magic faction and the Chaos Horde, a Chaos Magic faction.