Main characters ; : :Played by:
Tenka Hashimoto : The main protagonist, Mitsuki is a reserved and calm 15-year old who has been living with her stepbrother Yūya since her mother's second marriage. She initially has a cold view towards Yūya due to a bad relationship with her real father. Mitsuki is possessed and haunted by Hiyori's ghost and forced to help her pass on by helping her experience "lovey-dovey" situations with Yūya. Hiyori tells Mitsuki that the possession caused a chastity belt to appear on her. Each time the heart on the belt fills up, Hiyori is one step closer to reaching the heavenly gate. As the story progresses, Mitsuki remembers that Hiyori was a close childhood friend and rival in love with Yūya. She then learns from Neko that Hiyori is in fact alive (unknowingly) in
limbo, and that the chastity belt came from Mitsuki's own locked up feelings. Mitsuki becomes determined to help Hiyori reach the gate which allows her to live rather than to cross-over. ; : :Played by: Yukichi Kobayashi :Mitsuki's step-brother. An average Japanese high school student, Yūya's goal is to have a fine sibling relationship with his new little sister. He is generally good-hearted, but because he grew up without a mother and little companionship with females, he has an incredibly poor ability to understand and empathize with Mitsuki's feelings. He also has a tendency to make very inaccurate assumptions based on unusual circumstances, and despite his good intentions, his attempts to help Mitsuki often cause things to become worse, such as when she needed to go to the restroom, and he thought she was sick and forcefully dragged her to the school clinic despite her protests. Due to his misunderstanding about Mitsuki's chastity belt and Hiyori, he believes that Mitsuki and Hiyori are a "lesbian cosplay couple". ; : :Played by: Mayu :Hiyori is a spirit of a dead girl who is possessing/manipulating Mitsuki from time to time. Hiyori has no memories of when she was still alive, only including remembering her own name; the name Hiyori Kotobuki is not her real name. However, she remembers her love for Yūya, to the point of viewing him as her own older brother. Hiyori often pushes Mitsuki to engage in an incestuous relationship with her step-brother even to Mitsuki's extreme protest. Hiyori is also shown to be extremely athletic, displaying great talent in any sport as shown when possessing Mitsuki. ; : :Played by: Mika Yano :Yukina is Yūya's childhood friend. When the duo were young, she acts as the older sister to Yūya and is known by him to be quite tomboyish. As a teenager, Yukina grows more feminine and ladylike and develops feelings for Yūya.
Other characters ; : :Yūya's classmate and best friend, Shōtarō Torii wishes he had the brother-sister incest he fantasizes Yūya could be having with Mitsuki. However, he hardly ever gets along with his own sister, Moa Torii. That aside, he doesn't hesitate to flirt with girls of any age, younger or older, such as with Mitsuki's aunt, Nanami Akesaka. ; : :The rather quiet, glasses-wearing classmate to Yūya, Neko seems to know about Mitsuki's situation with Hiyori. She also has been in a position to help push the brother-sister relationship along, such as providing tickets for everyone to a water park owned by her father. In reality, it is quite possible Neko is directly involved in Mitsuki's and Hiyori's situation with the chastity belt, such as an agent of Heaven, as suggested by the anime's opening video. :At the same time, when Neko herself ends up a part of such situations, such as at the hot springs inn vacation, she refrains from showing off way too much skin, so she wears a one piece swimsuit to the bath. ; :Voiced by:
Manami Tanaka :Played by:
Kazue Akita :She is Mitsuki's classmate and shown as a good friend of her. ; : :Mitsuki's aunt, and a bit of a drinker, Nanami is charged with checking in on Yūya and Mitsuki while their parents are away. ; : :Moa is Shotaro's younger sister in middle school student. She and her brother barely get along, which makes Moa often wish she had a nicer older brother, like Yūya is to Mitsuki. While arguing with her brother, Moa often uses the insult "Bald"/"Baldy". ==Media==