SnowDrops (aka just another rewriten Harry Potter)

Full summary inside. Salazar and Helga were twins, and their reincarnations met Harry, and things changed. Rated T because I'm still not sure how the rating system works. Also, English wasn't my first language and this is my first fanfic. I tried to write fiction before but never finished any because I get bored easily. Let's hope I won't give up this time around.