Hiyori (日和, Hiyori) is a young girl who is a member of the Re-Code.
Hiyori has coral-pink hair, which is placed into twin tails, and matching pink eyes.
In her lost form, she becomes a small turtle. Her shell is a red color to match her normal hair color.
Hiyori has a happy-go-lucky personality, even when killing and attacking others. She had child-like innocence as much as a child-like cruelty. She was excited when she won the rock-paper-scissors match that decided who got to kill everyone, promising that she will make them suffer before they die, all while keeping up her child-like personality. However, this seems to only extend to people she doesn't know.
Her parents killed themselves due to a huge debt, leaving her homeless. She was presumably unable to control her powers, as the Re-Codes heard rumors of a violent, fugitive power user. Others saw her as a burden and as being worthless, causing her to hate people. When Rui, Yukihina, and Kouji found her, she attacked Rui, only to be hugged by her and turned into "family". When Rui betrayed the Re-Codes and left, she began to hate her.
She first appears with Shigure, meeting up with Yukihina. She notes that it had been a long time since they had met, going up and hugging him. When Shigure kills several men having a brawl, they are interrupted by the police. They play rock-paper-scissors to see who would kill them all, which Hiyori won. She destroys the entire downtown sector of the city, leaving giant holes in the street and buildings and killing all there.
She reappears at Shibuya Mansion to take Pandora's Box, setting up a trap to lure in Rui and weaken her, although she was fighting to kill Rui. Although Rui was about to lose, because Yuuki protected her and was injured, she regained the will to fight and defeated Hiyori. As she was about to kill Hiyori, Hiyori reverted to her Lost form, and so Rui did not kill her.
When Yukihina appeared, Hiyori wished for him to kill her, until she realized that Yukihina was there to take the Card Key, which was with Rui. During Yukihina's fight with Heike, Hiyori managed to take the Card Key and escape to "The One Being Sought".
Despite her loyalty to "The One Being Sought", even bringing him the Key, he later attempts to kills her and Shigure after obtaining Pandora's Box, believing them to be weak. She seems to be in the eternal lost form because the manga didn't show her as a human after she became a turtle
When Hiyori overuses her powers, she changes into a turtle, but still keeps the ribbons in her hair after her transformation.
Balloon (泡膜, Barūn) is Hiyori's Special Power and it allows her to manipulate different kinds of membranes. She can use this power to produce small, circular balloons from her mouth that explode on impact. These balloons do not create shadows due to their 100% transmittance of light and are immune the Rui's Zan-ei as a result. Hiyori is also a master of disguise, using her power to make a membrane that is able to take on the appearance of another person and mimic their personalities perfectly. The weakness of this disguise is that the real person can still be detected by scent. By kissing her opponent, Hiyori can take away their sight due to manipulating their corneas.
Balloon Arrow: Hiyori creates a bow made of membrane and fires numerous arrows at her opponent that explode on impact.
It was shown that she was very close to Prince, where it was her that saved her and got her out of her shell. However, after Prince left the Re-Codes, Hiyori grew an intense hatred towards her, wishing to be the one who killed her.
She seems to be very fond of Yukihina, as whenever she sees him, she is automatically latched onto him and simply hugs him for long periods of time (Yukihina in turn, seems to either ignore it and lets her or simply doesn't care). She also noted in her introduction that it had been a long time since she saw him.
Hiyori is usually seen around Shigure. She supports him in whatever does. In their battle with the "Angels", Shigure stated that Hiyori should be their sacrifice, since she was already in her lost form and she willingly accepted.
A lot of her power got drained off until Yuuki pushed her, beating the Rare Kinds' power with his speed of sound. He scolded her for being foolish, and told her to treasure her life. Hiyori then stubbornly rejected and said she'd be the sacrifice. But before that, she thanked Yuuki for saving her even though she was his enemy. She allowed her powers to get sucked out again when Shigure blocked her from it this time.