HP: The Unknown Century

At the end of the legend

There lies darkness that devours everything

But it is not completely without light

The eldest son of the French noble house of Brickel, a family with a thousand-year legacy, Alex became the only Brickel in several centuries to enter Hogwarts School of Witchcraft and Wizardry in Britain.

P.S. The original protagonist is not a transmigrator. Related to the Malfoys.