#devil!barty

There's a huge library in the Black family's summer house and Regulus decides to visit it (because it's better to do that than listen to his brother ramble on about Remus Lupin) and finds a diary.

It's a witchcraft diary from his dead great-grandmother written in Latin (because WE ALL KNOW LATIN IS A DEAD LANGUAGE, HAHA) and he decides to read some parts as a joke (because Regulus is a Black man and obviously Black men know Latin and are skeptical of all religions and supernatural things that exist).

And that just leads to having a demon stuck to your side all the fucking time.