What is the Thing and which historical figures have opposed it?

The Black Thing is evil. Think Darth Vader or Hitler. The Black thing personifies evil. Mrs. Which sums it up quite succinctly, "Itt iss Eevill. Itt iss thee Ppowers of Ddarrkknesss!" The evil in the Black Thing is absolute so you can take your pick of historical figures, in our world, that have opposed evil in the past. Consider people like Martin Luther Kink jr., anybody fighting fascism, or even people that you know who struggle against darkness.