So I just realised something super super dark whilst doing some work on COAs about House Qoherys of Harrenhal and the Hoares that they took the castles from.
Basically, the Qoherys sigil is the Hoare sigil, a quartered sigil with the quarters done diagonally but with each of the four elements of the Hoare sigil (the ship, the tree, the grapes, the raven) all replaced by the skulls of Harren and his family and with the chains of the ironborn replaced by the flames that killed them, all on the black of the Targaryens, the house that killed them and the colour of Balerion the dragon that burnt them alive
Nice Catch! Also don't know if it was intentional, but the Qoherys Sigil reminded me of a Jolly Roger, but instead of crossed bones the crossed flames and all that. I think is funny that the house who took over Harrenhall ended up with a more "pirate" like sigil than the Hoares themselves.
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