Vinata's six-guard retinue, one of whom converts each season to open the temple escape route.
There are usually seven of them in total: Princess Vinata plus six guards. Under Rosetta's theory, one guard is the sacrificial convert — she worships the light deity, receives Travel the Path and Welcome Home, and initiates a Prospect Congregation that packages the rest of the court for transport into the temple.
The absence of any worship sign or Smite mark on the sultana and her remaining guards is the clue that cracks the case: the missing guard is the one who actually converted, and she would stay behind in the temple rather than reappear at the end of the game. In three or four minutes the whole retinue is due to transfer to the Temple of Khepri.
The retinue whose head-count discrepancy exposes which of them is the convert.