The Doom Was an Inside Job / T + FM = D

In AFFC, the Faceless Men of Braavos seem to take credit for engineering the Doom of Valyria, and most in the fandom agree they had a hand in it. But the Faceless Men usually work for hire, and there's this weird Valyrian prophecy about the gold of casterly Rock destroying Valyria... so did someone hire the Faceless Men to do the deed? There's a strong case to made that someone did - the Targaryens of Dragonstone. In other words... T+FM=D, or, "the Doom was an inside job."