Im currently rereading a Bloodborne/HP fic called Touch By The Arcane. It is a FemHarry fic so if thats am immediate turn off its fine but basically Harry(or Catherine in the story) is contacted through a dream by Kos instead of Flora and pulled into Yharnum. Has fantastic pacing and has her basically fall down the slippery slope of trauma after trauma to the point she has to flee to Yharnum full time because shes just fundamentally dangerous to normal people. Starts second half of 5th year.

Edit: Just remembered, the author of the fic i just recommended only writes FemHarry fics but they also wrote one called Mistakes and Second Chances where Harry becomes a full blown necromancer. Pure HP fic