"D" stands for Many Things
Delirium, Desire, Despair, Destruction, Dream, Death, and Destiny are the family of the Endless.
They are not mortal, and their power is certain, as long as there are things to inhabit their realms they will exist.
And like all families, they are slightly dysfunctional. Sometimes the youngest play games with mortals in order to pass the time, but for the most part they stick to themselves.
They are not gods, they are far more terrifying and powerful.
This is how Harry Potter conquered them.
AUTHOR'S NOTE: Due to popular request, a disclaimer. This piece is metafiction, so I play with popular HP tropes (at least the ones that were out in 2007). There are some psychological aspects to it that some find off-putting, but other readers love.
One thing is for certain, there's not another story like it.