Azkaban was now a former shell of its previous intimidating glory, if it could be called such a thing to begin with. Little more than an island with rough hills of sharp rock, it would be the final resting place of Lord Voldemort
He had received a note magically glued to the forehead of one of his lower tiered Death Eaters. Both had been left in cinders.
'Dear Moldy Wart,
I think it's about time we settled the score. I'm going to stop hiding, and so are you. I challenge you to a formal duel, one weapon of the wielder's choosing, to the death. This duel will take place at the center of Azkaban, upon midnight, on the 24th of December. If you do not come alone, you will never find me, I assure you.
Signed,
Your Killer'
Needless to say, Voldemort had gathered every Death Eater with a Mark and every stooge under the Imperius. He'd also brought a giant and a dozen werewolves, to bear witness to his final triumph, and spread word of his infamy along their kind.
As he approached the center of the island, he noticed something unusual, something that hadn't been there before.
When he was close enough, he could see it was a marble pedestal, roughly waist height, with a metal briefcase and another note. He ordered the Death Eaters and werewolves to fan out, and the giant to stand off to the side.
He reached the suitcase and ran a few spells to check for trap, and finding none, he removed the new note and read it, eyes narrowed in suspicion.
'Dear Moldy Wart,
How good of you to come. I believe the duel commenced the moment you arrived on the island, so if I'm not mistaken you should be roughly four minutes into the duel now.
Time should be almost up, so I'll keep this short and sweet. The muggles, much as you hate them, have made some truly marvelous discoveries and inventions in the last century or two. As such I've decided it entirely appropriate to borrow one of their weapons for this duel. The Queen was very understanding when I asked her and explained the situation, and was able to procure this for me. It's a wonderful little device the muggles call a tactical nuke, and as the challenger, I'll go first.
Sayonara, sucker, and good riddance to your horcruxes.'
Voldemort glanced down at the briefcase and opened it, staring at the odd device within, and the glowing red number five, counting down.
In a flash of light, Voldemort and hid army were gone.
Meanwhile, having already found and dumped the rest of the horcruxes on Azkaban with the nuke, Harry celebrated Christmas very, very happily.