What if Filch from Harry Potter as a young caretaker at Hogwarts when he fell in love
with a young teacher. She was a witch, but Filch was only a squib and he felt he wasn't
good enough for a magical person. The teacher, however, was more in love with Filch
and decided that being with him was more important than being a witch. She recruited
her best student to perform a spell on her to remove her magic, in secret, to surprise
Filch. They scoured the restricted section of the library for a sketchy dark spell to remove
magical abilities. Finally, after they found it, the student performed the curse on the teacher
but the spell went horribly wrong. Instead of becoming a squib, the teacher, Mrs.Norris,
became a cat and since then Filch has always had a vendetta against students for what they
did to her. They guard the restricted section relentlessly so no others will make a mistake like
hers, and they stick around the school in the hopes, that one day, Dumbledore will discover
the counter curse, and they can go back to being lovers.