I see. Ok... Let me think about it. It's a fairly narrow parametrized corridor.
The creature, “the beast” should appear only during the storm. So there’s going to be something special about the storm (for example a billion joules of energy of a lightening) to bring it to life. It has to be ugly enough or scary enough to “stop their hearts”. It has to be someone or something that George can kill or scare away with the gun or defend with Dobermans. A note – it can’t be a cougar, for example, because cougar eats Dobermans for breakfast. In addition, when we say, “many knew of her secret” the “many” apparently refers to those creatures that appeared during the storm rather than to people let’s say around the neighborhood.