Chizu was relatively calm and a bit quiet, yet particularly disgusted by the one-track minds of her male classmates. Her chair was black and fancy, carefully designed, shapely, and looked very old.
While at school Chizu was in love with her teacher, but was being deceived. He lured her into a date and then blackmailed her to being gang-raped by his friends. For this reason she began to carry a knife with her at all times. After killing Kako Isao, she completed his battle. During the combat she revealed she was pregnant and used Zearth's power to kill all of the men who assaulted her except the teacher, because her older sister, who was in love with him too, stopped her. After her death, the rest of children figured that Chizu's baby (who died with her) was also listed in the contract, which means that one of them, besides Kana Ushiro, was not bound to it.
Just like Kako's story, Chizu's scenario had a lot of changes in the anime version. She was seduced by her teacher just like in the manga, but instead of being blackmailed by him, he sold some pictures of them having sex which ended appearing on the internet. Despite having the faces digitally altered, they were identified by her classmates, which led to him being punished by the school's principal. He begged for Chizu's forgiveness, and just after she accepted his apologies, she discovered he was also dating her older sister. After Kako's death, she was chosen to assume his place. Just like in the manga, Chizu tried to kill her teacher using Zearth, and was stopped by her sister, but the rest of the children just discovered about her pregnancy and the fact that one of them is not bound to the contract after her death, when Moji witnessed two slits blackening out from Zearth's face, representing her and her baby.