Some of the characters in the series include:
- Voiced by: Wataru Hatano (Japanese)
- The main character, a college freshman just starting a new life in the School of Literature at Tama University. His parents passed away when he was young. As such, he was raised by his sister, Yuri. He was angry with his sister's decision to marry a man who has two daughters from previous marriages. When Yuri and her husband go missing, their three daughters had no one to turn to. Yuuta makes a decision to take them in and becomes their guardian. He is surprisingly reliable. Even the youngest daughter of the three, Hina, quickly got close to him. He has feelings for Raika but couldn't find any chance to express his feelings to her, in the last episode of the anime adaption he proposes to her (which she accepts) just to symbolically act as Hina's mother for one day (while he act as "father") at Hina's nursery parents day.
- Sora Takanashi (小鳥遊 空, Takanashi Sora )
- Voiced by: Sumire Uesaka (Japanese)
- The eldest of the three sisters. She is 14 years old, second-year student in middle school, and has a tsundere personality. She normally refers to Yuuta as "older brother (Onii-chan)" and holds a longtime crush on him but he is (perhaps purposely) oblivious to her feelings and thought she is just a shy and short tempered girl. She also gets easily jealous when he is with Raika. She has fairly good grades in school but is not adept at cooking. She is jealous of Raika's body like a fashion model, her huge bust and also her close bond with Yuuta. Her style is highly reminiscent of Haruhi Suzumiya.
- Miu Takanashi (小鳥遊 美羽, Takanashi Miu )
- Voiced by: Eri Kitamura (Japanese)
- The second eldest of the three sisters; she is 10 years old, fifth grader. She has blonde hair as her biological mother has a Russian lineage. She normally refers to Yuuta as "uncle (Oji-san)". She has a preference for guys who are older than her and manly. It is implied that she may have a slight crush on Yuuta, as she is particularly curious about his romance life. She started develop feelings for Yuuta at the end of volume 4 of the light novel. Her biological Russian mother also makes an appearance in volume 4, but Miu decided to stay with Yuuta instead.
- Hina Takanashi (小鳥遊 ひな, Takanashi Hina )
- Voiced by: Hiromi Igarashi (Japanese)
- The youngest of the three sisters, Hina Takanashi is 3 years old and attends day care. She is the biological daughter of Yuri and thus the only one of the three girls who is directly related by blood to Yuuta. She is very friendly and unafraid of strangers. She sometimes mispronounces words, often leaving out certain consonants. She normally addresses Yuuta as "uncle (Oji-san)", but has trouble with the "j" and "s" sound so it comes out as "Oi-tan" (little uncle). She is a fan of the heroine anime, Luna Luna Seven.
Street Observation Research SocietyEdit
- Raika Oda (織田 莱香, Oda Raika )
- Voiced by: Yui Horie (Japanese)
- A second year student of Tama University School of Literature. A very good cook in Japanese cuisine. She is the only female member in the Street Observation Research Society. Everytime Sako has perverted thoughts or is crude, she beats him with a harisen (a giant paper fan). Despite being very attractive, she does not reveal her emotions easily and dislikes talking with anyone except for Yuuta, and teasing him with her body at times, hinting she has feelings for him. She especially loves cute things, as upon encountering one, she starts making strange squeaks and changes into a different person. This also applies to Yuuta's nieces, including Sora, who is awkward of getting on good terms with her due to her jealousy on Yuuta.
- Kouichi Nimura (仁村 浩一, Nimura Kōichi )
- Voiced by: Daisuke Ono (Japanese)
- University freshman of Tama University School of Literature. He is a good friend of Yuuta and a womanizer. He insists that his house is only for taking girls in. As a result, he almost never stays at his own home and instead spends time frequently at Yuuta's apartment, or at one of his affairs' places. He is however a very caring friend and will help out with chores on his own initiative. He also helps Yuuta keep Sako away from his nieces. He has a soft spot for Miu.
- Shuntarou Sako (佐古 俊太郎, Sako Shuntarō )
- Voiced by: Junji Majima (Japanese)
- A third year student of the Tama University School of Literature. He is the President of the Street Observation Research Society. Shuntarou has been a third year in the university ever since Raika enrolled. He is a lolicon and wears thick glasses. He once told Raika that "Love is justice. Love is the strongest." to justify his lolicon fetishes to which Raika later agrees, despite she usually beats him on with a harisen when he goes overboard. He has taken a certain interest in Yuuta's nieces, excluding Sora, who he claims she is too old for him despite she is only 14, and usually calls her "Oba-chan" (old lady).
- Yuri Takanashi (小鳥遊 ゆり, Takanashi Yuri )
- Voiced by: Sayaka Ohara (Japanese)
- Yuuta's older sister, Miu's and Sora's stepmother, and Hina's mother. When their parents died, she raised Yuuta by herself. She married Shingo when Yuuta was in high school. At one point Yuuta was mad at her because her husband had a previous marriage and because he already has two kids, Miu and Sora. She and Shingo went missing during their flight, which forced Yuuta to take her kids to his custody to prevent them from being separated.
- Shingo Takanashi (小鳥遊 進悟, Takanashi Shingo )
- Voiced by: Nobuo Tobita (Japanese)
- Yuri's husband. He was previously married twice and each had one child. Miu's mother divorced him and Sora's mother died. He is a cosplay otaku and thus he would ask his wife and daughters to cosplay for his photo collection.
Sasha Ilyinishna Gagarina
Sasha is Miu's Mother by Birth. When Miu was little she went back to Russia. After a few Years she came back to japan. Yuuta, Sora, Miu and Hina meeting Sasha in an ice-skating hall in Volume 4 (Light novel). Also Sora knows Sasha. In the end she must leave again for a short Time. In Volume 8 she comes back and become one of the main characters.
- Kurumi Atarashi (新子 胡桃, Atarashi Kurumi )
- Voiced by: Sakura Nakamura (Japanese)
- Yuuta's next-door neighbor. She is working as a voice actress and previously worked on Hina's favorite anime series. She plays with Hina and Miu during her spare time. Appeared only in the anime adaption.
- Sawako Midorikawa (緑川 佐和子, Midorikawa Sawako )
- Voiced by: Rina Satō (Japanese)
- Yuuta's rather inflexible landlady. She almost had Yuuta and the girls evicted from their apartment, had it been for the timely intervention of her mother, the real landlady. She, at 29 years old, is still single, and seems to be jealous of young couples; though she developed a soft spot for Hina. She only appears in the anime, in the light novel Yuuta's landlord is an unnamed male with a minor role.
- A lady Hina grows fond of.
- Shiori Kitahara (Kitahara Shiori )
- The Takanashi's next-door-neighbour, a senior high school teen girl. She holds a romantic feeling toward Yuuta, while also being antagonized by him, and feeling him as being a rival for the sisters affections, and guardian of there safety against the creepy uncle.
- Mrs. Kitahara is the Takanashis' next door neighbour, a former teacher.