You decide to eat the souls of the insane, and the death eaters. You go to the lower floors because that seems to be where they keep the more dangerous criminals. As you go deeper you see more and more Dementors, which have a humanoid shape, and are covered in dark hooded cloaks of long, ripped black cloth. Their body is greyed and decayed looking, like a decomposing corpse, and their breath sounds rattling. Their hands are glistening, greyish, slimy-looking, and scabbed and you have heard they exude cold, but you don't feel it.
They seem to ignore you, partly because of Faceless Syndrome, but mostly because you have few emotions. As you go deeper you also see a few gibbering recks rocking back ad forth, and even a couple of dead bodies. The cells are all the same, iron bars on the front, worn and dirty mat in the corner, and a hole for waste in the other corner, and, judging by how overflowing they are, the holes aren't cleaned often, if ever.
You eventually find a person that seems crazy and has the Dark Mark, you don't think anybody will miss him. It is a tall man with matted brown hair and a crooked nose, he is curled up in fetal position on his mat and is muttering to himself. On his arm you can see the Dark Mark, a black skull with a snake coming out of its the mouth. You unlock his iron cell door with your Keyblade, go up to him, graph is head, and pull the soul out of his body.
You start to eat it, then...pain, pain, PAIN. Depression, despair, no happy, happy dead. I die, death good, no more PAIN. Let me die, let me die. That you Death? Save ME! No, no, no, death is too good for you, THEY won't let you die. Soon, THEY don't let you hurt anymore, don't let you feel, even the pain is better now, but no, not for you. You deserve it don't you? You don't remember, the cell is everything, there was nothing else. The cell is gone, there is just you. You are gone, there is nothing now, no pain, no despair, just NoThInG fOrEvEr.
You rip the soul out of your body and it goes where ever souls go, you don't really care about it right now. Several Dementors seemed to have been floating around you, but they leave when you get rid of the soul. You just sit there, in the cell with the empty body, shivering and trying to recover. You eventually feel well enough to leave, and you were planning to sacrifice a few souls to the Darkness, but you don't even want to think about souls right now. So you just start looking for Sirius Black, passing by more and of the insane, the empty, the soulless. They don't even murmur any more, now there is just silence. In the deepest levels you eventually see a large black dog sleeping in one of the cells, an unregistered Animagus most likely, since there is no reason for a dog to be down here.
[] What do you do now?