Hanae Suetsumu works as a nurse at a B.A.B.E.L.-owned hospice, specializing in end-of-life care. She possesses long blue hair and brown eyes but consistently uses her hypnosis ability to project a conventionally feminine face, masking her natural broad and masculine features due to deep self-consciousness and fear of frightening others. Her personality includes masochistic tendencies, particularly evident in interactions with Fujiko Tsubomi, where she justifies and enjoys physical abuse.

During the Elementary School Arc, Tsubomi enlisted Suetsumu to manipulate Kōichi Minamoto. Suetsumu transformed into adult versions of each member of The Children to foster romantic feelings in him. Minamoto, aware of the hypnosis, resisted the plan. The real Children intervened and halted the scheme. Later, Suetsumu served as a maid for Tsubomi during New Year's celebrations at Tsubomi's holiday home. Shiho Sannomiya accidentally saw Suetsumu's real face and fainted, mistaking her for a ghost. This prompted Minamoto's suspicion, leading Suetsumu to reveal her true face to him directly.

In a subsequent storyline, Suetsumu provided comfort to her hospice patient Oobata. He confided in her about secretly being an esper and detailed his future-controlling psychic abilities. In the anime adaptation, he gave her a notebook infused with this power.

Her primary ability is hypnosis. Professionally, she uses it at the hospice to allow dying patients to see deceased loved ones. Personally, she maintains her altered appearance daily to present what she considers a more aesthetically pleasing face.

The etymology of her name reflects floral themes: "Hanae" combines "flower, blossom" (花) and "branch" (枝), while "Suetsumu" derives from "end, close, tip" (末) and "pinch, pick, pluck" (摘).