Background:
Harry is dying of AIDS, a curse in its own right that was forced upon him by the rape of an unknown wizard when he was 14. Horribly ill, and among the masses of poor wizards of Great Britain, Harry cannot afford the only magical cure. He cannot interact with others because he would spread the disease with any close contact.
Powerful and evil Dumbledore, current leader of Great Britain, picks him and brings him to a facility where he is kept in isolated quarters, served sanitized food through a whole in his door and can only talk to outsiders by their use of a microphone. He is constantly observed through a one way mirror and he is basically a test subject to observe as they watch his strong and independent will die as his strength and power are drained during the time the disease takes its hold. He losses his hair, gets skin diseases, has trouble breathing, etc.
Near death, Dumbledore comes to him and asks if, in exchange for the cure, he will work solely for the 'light' side as a weapon. Feeling near the brink of death, Harry agrees and is given the cure. He awakes after three weeks in almost surprise and sees himself in a hospital bed. He looks around and notices himself in the mirror. 'Cured' is the first thing he notices.
Harry has undergone major changed during his recovery. He is healthier- more filled out without any signs of previous malnourishment. He has a lethal build and is extremely flexible. His eyes are a captivating bright green and his eyes have a permanent circle of black (think, permanent dark black eyeliner on both eyes- upper and lower lids). His hair has a shine and health to it it never had before. Along with it's darker black color, it has obtained a more contained look and it's messy appearance looks purposefully done. He's skin is clear and attractively pale. He has well care for nails, better muscle control, perfect sight, and quicker reflexes. He's never felt or looked better.
Dumbledore approaches Harry again. He informs him that Harry is cured from the EFFECTS of the curse, and not the curse itself. When he thinks his devastation cannot get any worse, Harry is told that his agreement forced him into a magical and life binding contract with very clear rules. Harry is to join the Dark side and dismember them from the inside out by spreading the virus through the Death Eaters, dark allies, and eventually Voldemort himself. Due to the affects of the cure, the only way for him to do this, is to have sexual intercourse with his victims.
Plot:
As the unwilling weapon of the light, Harry must enter and join the Dark forces, destroying them from the inside out. Makes his way through the ranks with his prodigy-like abilities in the Dark Arts, Harry learns things he never knew about the war and the Dark Lord himself. As Harry falls in love with the Dark Lord, his plans and his life are put in jeopardy as he battles with his situation. His task must be completed or he will die.
Things not to Change:
Tom/Voldemort and Harry Pairing though, if you wish, it can be one-sided.;
Rated M;
Dark!Harry;
Harry's disease;
He's extremely attractive and tempting