Disclaimer: Harry Potter & Co. belongs to JK Rowling.
Every Saturday, Harry writes to Voldemort.
He has no idea why he does it and while he's on that topic, he doesn't particularly care. It is perhaps the only thing he can predict happening in his life. Nobody knows, of course. He's had enough distrustful glances and suspicious whispers behind his back to last a lifetime and beyond.
There is no fixed topic, either. He writes about everything - sometimes romance. Like how Dean and Ginny kissing in the Great Hall and Ron's reaction, Ginny dumping Dean a few months later. Not often (but sometimes) his own love-life comes into play. Lavender Brown kissing him after a Quidditch victory party and their brief relationship that followed, or how Blaise Zabini kissed him in the boy's toilets. Other unimportant details are written down, too. Quidditch scores, class work, homework rants, detention complaints and other such tings.
The stream of scrawled words appears careless if taken at surface value, but Voldemort has learned to look beneath things like these. Every Saturday evening he unties the letter from the leg of the snowy white owl and locks himself in his quarters to read it.
In the privacy of his rooms, Voldemort allows himself to let down his mask. He reads with the frown on his face and once, at a particularly snide comment in the letter, he let out a short laugh. Even now he looks back on it and tries to remember what that brief moment of joy felt like.
After a while the letters become darker and more personal. Harry writes of how alone he feels, how everyone has drifted away, the pressure he feels and how he is losing the will to fight. He also often says he doesn't know why he tells Voldemort such things, but Voldemort harbours the fancy that he is the only one who isn't close enough to the boy to judge him.
Then one day a final letter arrives, off schedule. It is a Monday and Voldemort is in a meeting, briefing the Death Eaters on their next raid when the familiar white owl comes. It flutters through the open door and comes to perch on his throne, dirty and exhausted. Weakly it holds out its leg where a scroll has been hastily wrapped. Feeling thrown off guard Voldemort unties it and under the curious eyes of his followers, he unrolls it.
It is splattered with blood but he reads the scrawled words with ease. There is only a sentence:
I'm dying and I want you to know I choose this.
Angrily Voldemort dismisses his followers and stalks to his quarters. He is confused; there are feelings inside him that he has no idea how to decipher. Finally he turns to his serpent who is more human than he is and asks for her opinion. When she finally speaks, her words are hesitant. She tells him it is sorrow.
With the boy dead, it is only too easy. The entire Wizarding World is in mourning, mourning for a boy they never bother to know. They are weak in their sorrow and they fall easily.
Some ten years after Harry Potter's suicide, Voldemort retires to his quarters, exhausted by life in general. He sits in front of a roaring fire and stares into the dancing flames, a glass of amber liquid in his hand. Nagini twines around his shoulder, pressing her serpentine face to his own serpentine face. He shifts his gaze to the glass and stares at it for a long moment.
Then he raises his glass for a long moment, throws back his head a drinks. He drinks to Harry Potter, the only one (besides Nagini) to make him feel like what he once was but will never be again.