The strange blade glinted in the moonlight. The man who held it knelt at the center of a circle drawn on the floor. The circle itself gleamed wetly, it's color matching that of the dark fluid running down from his wrists. His voice was simultaneously growing weaker and echoing louder as he spoke.
"Essence of Shadow, heed the call of my blood. I offer my blood in sacrifice for the powers of these creatures, whose essence I hold. Form and function, I call for thee."
On the floor before him, but within the circle and easy reach, lay four bowls. Each contained pieces from different creatures, all of whom were associated with darkness. Spinnerets of an acromantula, wing bones of a bat, fang of a basilisk, and part of the shroud of a dementor. He let his blood spill into each of the bowls, and then carved the necessary runes into the skin of his chest. The circle began to glow, radiating a sickly green light, as smoke began to emanate from the bowls. The smoke poured into the runes, causing them to glow with the same eldritch green light. Soon, the ritual was complete, and the man collapsed, blood loss finally taking it's toll. A shorter creature came out of the darkness, muttering to himself. He seemed rather pleased as he snapped his fingers, causing the man's wounds to close.
"The master has done well. Kreacher thinks the Mistress would be very pleased, he does."
Kreacher snapped his fingers again, levitating the man's limp body out of the room and into a bedroom down on the second floor. He tucked the man in with a kindly look on his face.
"Yes, Master Harry Potter, Kreacher thinks the Mistress would be very proud of you."
Ron and Hermione were both looking very nervous as the entered the front door of Number Twelve Grimmauld Place. Neither of them had seen their friend for several weeks, since the funeral for Ginny and the children. Ron could only imagine what his friend was going through, Hermione was more concerned about what Harry was going to do. After the funeral, Harry had refused all contact with friends and family. He had holed himself up in Number Twelve, and refused entry to all visitors. Ron feared for Harry's safety, but Hermione feared for his sanity. The look in his eyes as he stood there listening to others eulogize his wife and children bespoke of a man crushed between rage and despair. His physical wounds had mostly healed, but Hermione feared the emotional scars may just be too much for her friend to bear.
"Hermione? Are you sure about this, love? Harry's not going to be happy we're here, you know."
She shook her head, and led the way into the house, ignoring her husband's desire to ignore what she feared was his best friend's descent into madness. She started towards the study, but stopped when she saw Kreacher skulking down the stairwell with a breakfast tray in his hands. Upon seeing them, the house elf froze.
"The blood traitor and his mudblood mate. What does they want, we wonders?"
Hermione stifled her anger at the slur, and said "We're here to see Harry. Where is he, Kreacher?"
"The Master is sleeping. Not to be disturbed. Won't like being woke, he won't. Might blame Kreacher."
Hermione rushed up the stairs, leaving behind a bewildered Ron. She shoved open the door to the master bedroom, and gasped as she saw Harry laying there. The runes he had carved into his chest were quite familiar to Hermione, although she could not believe she was seeing them on something other than the page of a book. His sleep seemed peaceful enough, but Hermione remembered how Ginny had said he was always quiet, even when he had nightmares. She went over to the bed, and sat down on the edge, placing a gentle hand on his chest.
"Oh Merlin, Harry, what have you done?"
The sound of her voice caused Harry's eyes to snap open, startling her. His eyes seemed to glow a sickly green for a moment, but that moment passed quickly. He seemed confused.
"Hermione? What are you doing here?"
She reached up to place a hand on his cheek, and then took him by the chin.
"I'm cleaning up one of your messes, as per usual. What in Merlin's name have you done to yourself this time?"
"And who says I've done anything to myself," Harry said coldly.
"The runes you carved into your chest, Harry. Honestly! What were you thinking? How could you do something do something so horrible? What would Gin-..."
Harry's harsh glare, and the deep throated, inhuman growl escaping his lips silenced her immediately. His voice when he next spoke was deep, gravelly, and menacing.
"Don't you dare finish that sentence, Hermione. What's done is done. I'm going to make them pay for what they did to my family."
Hermione stood up, closing her eyes.
"Why didn't you come to me or Ron for help, Harry? We could have helped you. There was no need to do this to yourself."
He threw back the covers and stood up next to the bed, the shadows covering the upper half of his body. In the darkness, his body metamorphosed into a monstrous creature with large pointed ears, enormous wings, fangs, claws, and eyes that glowed with a sickly green light.
"You have a family now. Children who need you more than I do. Neither of you can go where I am going."
Harry closed his eyes, and resumed his natural form, although his eyes continued to glow in the dark. He took her by the arm, and led her back downstairs where Ron had decided to retreat to the kitchen. He was just putting the finishing touches on a large sandwich when he saw Harry's eyes.
"Bloody hell! Harry?! What did you do to your eyes?"
Hermione was unceremoniously pushed into Ron's arms.
"Take her home, Ron. And no matter what you hear, or what you see, do not come after me. I'm part dementor now, and chasing me is not a good idea. Oh, and one more thing. Both of you practice your Patronus charms."
With that, Harry walked into the shadows behind the door, and vanished into them.