This is an image of the priesthood of flutterwest during the lunar rebellion, the priesthood started as monks in a small chapel in the woods named flutterwest, when the changelings invaded in the year 735 the priesthood took up arms to fight the menace, led by the now famous archangel, whom at the time was an average priest: Edward blaze, after the changelings where driven back east, the priesthood was made into a special unit of Celestia’s military, under the direct control of her and Edward, during the lunar rebellion they stayed loyal to the sun princess and slayed the lunar heathens with almost terrifying skill, at the battle of manehatten during the lunar rebellion, 10 of the priesthood battled 250 heretics, and burned the shrine to luna that the bat-ponies had set up, when the war vs king sombra erupted, they proved to be stronger than 50 of the best royal guard units, Edward marched up to sombra and with a single blow from his blade “ignis lux” he killed the dark lord, during the time of modern equestria, they stayed quiet for a while. 
when nightmare moon returned, Edward rushed to celestia’s side, only to find that nightmare moon was transformed back into luna, Edward still wanted to torture and kill luna, Celestia stopped him. 
when the great war broke out between the zebras and the ponies, they did not join in the conflict, they where told by Celestia that they should not join, after demanding a reason why, Edward talked in private to Celestia and while they are the only ponies whom know what was discussed, something Celestia said changed Edwards mind about the conflict, when the mega-spells ravaged equestria, the priesthood had a specially crafted stable build deep underneath flutterwest chapel, it was made of magically-empowered gold that could survive more than one hundred mega spells detonating on top of it, the door (made of a specially enchanted gold, that would never grow dirty and stay polished for ever) had the symbol of the sun painted on its front and had no number (unlike the other, less important stables out there), while Edward was given the power of immortality millennia ago, the rest of the priesthood was still mortal, while centuries passed on the surface, Edward taught the priesthood the ways of combat, the teachings of Celestia, and most importantly how to wield magic even if you are not a unicorn, after transforming the priesthood from a simple combat unit of priests and paladins, into the most terrifying army of celestial fanatics, the doors of the flutterwest stable swung open, the steel rangers where waiting on the other side, they had been trying to open the stable doors for decades, but they did not expect an army, one thousand strong, wielding enchanted swords and bolters, they soon spread across equestria, spreading celesisim and slaughtering evil, where ever they could find it, Edward and two of his best priests, who we now know as saint fireheart and saint skylight 
marched up to canterlot, the pink cloud proved to be useless to stop their advance, as the power of Edward was so strong that in his mere presence the cloud was sanctified and transformed into a golden healing-mist, using holy magic, Edward brought Celestia back from death and together went on a crusade to cleanse the world of evil.
 
the priesthood is based on the sisters of battle from warhammer 40k