There is a 1% chance of finding one of the Justiciar Ghosts when you open a hallowed coffin at the Hallowed Sepulchre minigame. I wish each one of them rewarded you with a piece of gear, they can be decorative saradominist white-and-gold robes, or even some kind of agility/magic based gear that stand on the same grounds as infinity robes with a prayer related passive effect that interacts with magic.
#Justiciar Ghosts Should Reward
crimson pier
hollow panther
they reward you with lore and their invisible presence in the lobby