The statue rotates approximately every 48 1/2 minutes. The cycle it followed while I was there was Arcane (NE), Shadow (SE), Nature (SW), Light.(NW).
While I was killing in Shadow with no one else in the zone, Peacekeeper of Anriella (Nature) spawned. It happened near the time of rotation, so I might have killed after it rotated and my kill in Shadow triggered it to spawn in Nature.