After defeating Voldemort, the Malfoy family was not imprisoned in Azkaban because of Harry's defense, and their relationship became good in the eighth grade.
Afterwards, Harry and Ron became Aurors, Hermione went to the Legal Department, and Draco went to St. Mungo's Hospital of Witchcraft and Wizardry as a therapist. Under the leadership of Harry and the others, Bryce and Pansy began to put aside their prejudices, began to understand Muggles, and became famous fashion designers. At least in the Muggle world, no one knew that they would discriminate against them because they were purebloods.
Soon after, a force emerged in the wizarding world and began to integrate the pure-blood nobles who had not yet been purged, hiding them in the Muggle world.
The third Dark Lord rose up and founded the Demon Cult (seems like a bit of a drama?), Controlled by three demon lords: Lucifer (Harry), Samael (Ron), and Lilith (Hermione).
It took them five years to take control of the wizarding world.
Finally, they found the last person involved in the purge plan in the Department of Mysteries, who was hit by the dark magic he sacrificed his life for, fell into the Veil, and returned to the past. (They could actually break away, but their lover has left. In this world, they have no meaning in living, so they choose to leave after the revenge is over.)
Involving Deha (Draco x Harry), Panh (Pansy x Hermione), Bro (Blaise x Ron)
Concept: Time is the most magical magic in this time.