She is the MC's childhood friend who invites him to the Literature Club whom she just happens to be the vice president of. Sayori has a bright, vibrant personality, even if she can get a little klutzy. As for her voice she was a tough one to pin down, I imagine her as soft and cute, not to deep but either low light pitch sounding with a hint of compassion and understanding, I couldn't think of a voice actor similar to it, if you think you know how she should sound like then give it a shot!