Hannah

Hannah is ones of Sai's closest friends and his real-life crush in  The Literature Club! series.

She is friends with Sai, Emily, Aryan and Sayori and is acquainted with all of the club members. She was one of the most devasted characters after Sayori's suicide, after Sai.

Personality
Hannah is a sweet-tempered girl and is normally one of the most optimistic members of the club, after Sayori and Emily. However, her emotional volatility is very high, just undermining Yuri. An example of this is when she falls to the floor, just because Sayori stated she was depressed, and how she effectively made the situation worse for herself, and others after this. You may think that she could be to blame for Sayori's death, but she isn't.

After Sayori's suicide, she was left in devastation, and although not seen in the actual episodes, she actually cried herself to sleep many times and was sick almost every day.

Trivia(optional)
I've (Sai's) heard that Hannah actually used to have separation anxiety.