AN: BtVS and Harry Potter are not my property.
The beginning of the end came for Voldemort on All Hallows Eve. This was the evening he motioned his master plan into effect. A campaign of destruction against all the filthy muggles, mudbloods, and blood traitors swept across the country side. It was also the night he inadvertently birthed his downfall.
Voldemort sent his top enforcers to the highest of profile targets. The Ministry was swarmed and all those lacking the Dark Mark, died bloody. Diffindoed, Bomardaed, and Reductoed in the back as they tried to run to sanctuary. Anti-Apperation and Portkey wards kept them kenneled in.
Mad-Eye Moody was dead with the first wave. They got Arthur Weasley as he shielded Percy with his body and before his son could wipe the blood spatter from his eyes, he to was dead.
Nymphadora Tonks slipped in the pool of blood and passed on before she could even get to her knees. Kingsley Shackleboldt made it all the way to warning the Minister before he succumbed to his wounds.
Rufus Scrimgeour was hit in the chest with a killing curse as his advisors, Cornelius Fudge and Delores Umbridge, fled for the floo, having failed to realize the fireplace held only flames.
And on the Death Eaters went Reveling in the Destruction.
The shops of Diagon Alley were smashed, its patrons and shopkeepers blasted with all manor of hexes and jinxes till those wielding the wands grew bored. The Weasley Twins managed to escape to the Burrow when the most ferocious attentions were turned towards Olivander.
There they found the Burrow, where Harry Potter spent many a happy summer and themselves a glorious childhood, was surrounded by lower echelon Death Eaters. Watching as it burned with Fiendefyre. Ron and Ginny appeared to have made it out of the inferno. But their horrified faces stared back, mounted on conjured pikes. With a look they communicated a new course of action.
And through this Harry Potter, caged inside his mother's wards, screamed himself raw, then bloody as Voldemort thrummed with enjoyment while Vernon Dursley tried to beat him into silencing his freakishness.
Harry witness the annihilations through Voldemort as Voldemort monitored his followers progress, spying through what he marked on their arms.
And when the day dawned, England was now a killing field. More bodies decorating it than stones at Hogwarts. The Death Eaters finished their grueling work and filtered back to their Dark Lord. As the last arrived Harry Potter was finally able to welcome unconsciousness.
When Harry eventually came to it was to find that the Dursleys had fled. Himself no longer a boy but a changed man. Harry willed himself to Hogwarts, still in his day old clothes. There he found it deserted and untouched by the massacre of last night.
He sook out the sorting hat and the Sword of Gryffindor. Grasping the sword he'd slain a basilisk with he felt it change. A Glamour bleeding away leaving a plainer, sturdier blade.
The sorting hat murmured, "Godric and Salazar may have differed, but even they agree, the world has become a nightmare. Put me on boy and Rowena will show you how to end this."