Ok so I guess you all would be confused as Ik my writings are crap, so I'm here to clear things up.

   Yuri

-Likes Natsuki but unsure of the feelings so she wouldn't confess yet

-Is that serial killer as she had that lust for blood, when she can't hold it she would go out and kill people. But mostly unconscious while killing people. You can mostly know the differences of two Yuris  by the description of  her eyes, she normally has pupil but when angered or in the mood of killing, would be just in dark shades of purple.

 Natsuki 

-Doesn't know that she likes Yuri as 'like-like'

 -Thought that Yuri is just a friend

Sayori

-Likes Monika, A lot.

-still have depression ;(

Monika

-Likes Sayori

-Is kind and caring (As MC is one of Yuri's victim)

Hope this could make things clear for you all :D Feel free to comment if there are something that bothers you :3 

Have a great day or night <3