A cute, lazy girl who heads the Election Management Committee. Tachiarai has silver colored hair with a pink tint tied in two long pigtails. Due to her constant sleeping, she wears a light pink nightshirt with matching socks and gloves, and a light blue sleeping mask with the phrase "I CANNOT WORK" printed across it in kanji. She is always seen on top of a white body pillow. Despite having genius-level intellect, she was placed in Class 1 due to her refusal to exert herself.