Saki Kirishima is a 15-year-old high school student with spiky brown hair and distinctive purple eyes, standing 158 cm tall with measurements of 90-60-86. She typically wears her school uniform or casual tomboyish outfits.

As a member of the writing club alongside Yumeji Fujiwara, Isana Tachibana, Takateru Akiyanagi, and Mei Hoshino, Saki radiates cheerfulness and energy. She often playfully teases Yumeji about his bond with Isana. Despite her outgoing demeanor, she becomes shy and flustered around romantic situations, particularly when alone with Takateru, suggesting unspoken feelings for him.

Saki harbors a deep fascination with Yumeji's supernatural ability to perceive colored auras that reveal people’s impending dreams, though she possesses no such powers herself and remains an ordinary human. Her connection to Takateru takes a pivotal turn when Yumeji reveals Takateru has become the vessel for the dream demon Heracles. This news plunges Saki into worry and confusion, yet she trusts Yumeji’s resolve to save him. Until Chapter 40, she remained unaware of dream demons' existence.