Their friendship is one of the cutest in this manga. I am so glad that their friendship was not affected by their past lives that much. My memories are fuzzy, but do we know how they became friends? I think they are the closest of all their classmates.
Currently rereading this manga, and it's so funny how every time I think of something, I check the comments and find my comment from years ago about the same thing that I have no memory of writing.