The banner of the Harvest Brotherhood is also the banner of the city of Harvestveil. Within the banner, you can see the tree of Materan as well as the Seed of Profit
The Harvest Brotherhood are an extremely secretive order within the Empyrean Church. Known outwardly as farmers, bankers and bureaucrats, the Brotherhood controls food production and storage across Findle, Thessan and Morat Ras. The brotherhood provides support to farmers and ranchers in exchange for donations and has close ties to the Stormlords who provide adequate rainfall in times of drought. They are generally priests of Materan but do also count druids, bankers, bureaucrats and farmers among their ranks.
The Brotherhood openly headquarter themselves within the Temple of Materan in Harvestveil, although this is not where they store their vast wealth. Nobody outside the order knows the location of the Harvest Brotherhood's main vaults.