Harry Potter and the Favour of sweet Death

Both Ron and Hermione drowned in the Chamber of Secrets after they destroyed Helga Hufflepuff's cup. Remus and Tonks sacrificed themselves, leaving but a son behind, Luna got killed by a dementor's kiss, Fred was killed by the Death Eaters, Ginny had her nervous system crushed by numerous rubbles and now lives like a plant. Everyone who has survived the Second Wizarding War was a mess, some faring better or worse.

Sadly, our favorite Boy-Who-Lived is one of the ones who are faring worse. He sends Teddy to live with the remaining Weasleys, knowing he can barely take care of himself, let alone his godson. Things don't get much better for him when he's given the news of his insufferable older cousin, Dudley, having been murdered by the remaining Death Eaters after refusing to give them information on Harry's whereabouts.

Having had just reconciled with him and even starting to view each other as brothers, the death of the young man in order for the younger to stay safe, hits Harry harder than a truck.

As if all of this was not enough, as years pass by and the others start to grow old and gray, Harry stays the same. Always youthful, always healthy, always seventeen.

Not being able to handle this anymore, Harry does what any suicidal maniac would do;
Make a deal with death.

(Obviously, the characters don't belong to me, nor does the world of Harry Potter. It's all the work of J. K. Rowling.)