I've lost this manga I was reading quite a while back...basically it had a school where lots of students have these letters/notes that make people suffer misfortune, I remember a scene of a girl crashing through a window on a high level and the main protagonist has a boy bestfriend who has kind of girlish hair and kissed her for some reason....um, I think these notes were passed around the classroom, it's sort of like a countdown of students, one by one falling to a demise.
Hope this helps, I've tried the advanced picking all the genres it might apply to and it didn't come up.

Uroboros no Wa ?



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Even though I walk through the darkest valley, I will fear no evil, for You are with me.

Yes, that was it! Thank you!!!!!