To spawn this mob, clear the three groups of mummies on the ledge. The groups are all groups of six level 55v mummies, one vassal of offering per group and the rest a random mix of the Anuk' Sul decars/Faro' Nuk veterans/Sulite lunas found all through Priestess' Court. For each group killed, a moveable orange and blue striped vase will spawn. Move it to the triangle shaped area in front of the Rin Priestess' door.
For each vase placed, there is a chance to either spawn two offering retrievers (55^^) or the Rin Priestess of the Fyr'Un (55^^^) and two offering retrievers (55v).