Hitomi Karuko is an author who appears in the anime The Severing Crime Edge. Her background reveals her to be a talented pianist and a blind woman who runs an inconspicuous bar named Velvet, located in the street alleyways where the father of one of the main characters, Iwai, is known to frequent. She owns a specific killing good, a piano called the Pianissimo of Ecstatic Symphony, which has the lethal ability to kill anyone who listens to its music until the very final note. Because of her blindness, she relies heavily on her Instead, Houichi Koizumi, who is deaf. This pairing is significant as it allows her to play her piano fully without harming him, and he assists her by managing the bar, tuning the piano, and disposing of the bodies of her victims.

In terms of personality and role, Hitomi is a supporting character who, despite being an author possessing a deadly tool, does not share the primary goal of hunting the central character, Iwai. While other authors seek to kill Iwai to have a wish granted, Hitomi is portrayed as a beautiful but sinister figure who is disinterested in that pursuit. Her bar serves as a meeting place where other authors and characters can be encountered, and her existence helps to expand the world of the story, showing that not all authors are actively hunting the main protagonist.

Regarding her development and motivations, there is no detailed information available. Her key relationship is with her Instead, Houichi Koizumi, who acts as her caretaker and assistant in her murderous activities. Her notable abilities are intrinsically linked to her killing good; she is a master pianist whose performance becomes a weapon. The danger of her ability is neutralized only for those who cannot hear the final note, such as the deaf Houichi. Her physical appearance includes green hair and purple eyes. No other significant details about her personal motivations or character arc can be confirmed.