The stern and devout leader of the Whitewater Worship in Arimachi. Mustaf publicly denounces the party for their actions against an acolyte but ultimately accepts their rite of reconciliation. He leads a saltwater cleansing ritual and accepts Vash's feyglass opal as a meaningful offering, interpreting a distant splash as the Brine Mother's agreement. He upholds his promise to end the Whitewater Worship's persecution of the party.
Mustaf leads the Whitewater Worship.