Reiko has chin-length, pale gray hair, parted to the right, hanging down over her eye and obscuring the majority of the left side of her face. She has dark bags under her blue eyes, and a small mouth with full lips. Her hands are usually held up as high as her elbows, with her hands draped down, this gesture being somewhat connotative of a ghost.
Her hero costume consists of a white, knee-length kimono with a furred collar, three dark straps around her waist, knee-high socks and a black mask which covers her face from the bridge of her nose down, like the one always worn by Mezo Shoji.
Reiko is a quiet and emotionless teenager who often shows a odd body posture, wherein she keeps her elbows to her side and lets her hands dangle, which somewhat resembles ancient depictions of zombies, ghosts, and other undead creatures, alluding to her Quirk.
She also appears to be quite verbose with her wording, to the point where Reiko's classmate needed to simplify what she had said.
- Reiko's name contains the kanji for "willow" (柳?) and "child" (子?) and the katakana symbols for the rōmaji word "rei" (レイ?), which probably stands for "spirit; soul" (霊?).
- Reiko likes Internet surfing.