Nana Ebina

One of Umaru's friends and classmates. She hails from Akita Prefecture, where her family runs a farm. She moved to Tokyo to attend Arai High School and lives alone in Room 103 of the same apartment complex as the Doma family, "Corpo Yoshida." Her family and friends from Akita call her "Nana," while Umaru, Taihei, and Bomber call her "Ebina-chan." Kirie and Sylphynford address her as "Ebina-san," and her classmates refer to her by her surname, "Ebina." Although she usually speaks standard Japanese, she often slips into her dialect when she eats something delicious or gets nervous. Her birthday is October 19th. She is 155 cm tall and has blood type O.

Nana is timid and extremely shy but is also considerate of others and kind to nature, making her a compassionate person. However, she tends to keep her problems to herself, only confiding in Taihei about her brother and seeking advice from Umaru and friends the day before a test. When nervous or embarrassed, steam seems to come out of her head, and she often makes an "awawawawa" sound.

She has chestnut-brown hair styled in twin-tails with red and white hair ties resembling shrimp, and she has a noticeable large chest inherited from her mother, which draws attention even when she moved to Tokyo. Despite her slender build, she has a hearty appetite and often worries about her stomach growling when hungry. To suppress the sound, she tends to hold her chest with her arms, emphasizing it. She prefers cooking her meals and has two refrigerators in her kitchen.

Although she admires Umaru, who excels in both academics and appearance, she feels a slight complex about herself. Despite her hard work, her grades and sports performance are not impressive, and she is a poor swimmer. She is also clumsy in her daily actions. While she is not inherently bad at studying, her test scores were poor due to test anxiety, which she overcame by studying with Umaru and friends. She is perceptive, quickly noticing Kirie's true nature when she was isolated in class, and like Taihei, she is very good at rock-paper-scissors. She has helped with her family's farming since childhood and is good at weeding. She is also skilled at sewing, making mittens and bandanas as birthday presents for Taihei.

Taihei was the first person she met and talked to when she moved into the apartment, and she developed a secret crush on him almost at first sight. She also saw a resemblance to her missing brother, Koichiro, in Taihei's demeanor. Her feelings for Taihei are unknown to him and her classmates, except for Kirie, who later found out and declared she would fully support her. With Kirie's encouragement, she tries to make progress with Taihei but often ends up fumbling.

In a scene from a life simulation game played by Umaru, Taihei, and Kirie, an image is shown of Taihei, who left his job to open a restaurant, marrying a woman resembling an adult Nana and having three children.

Nana is searching for her brother, Koichiro, who went missing when she was seven. She only confided this to Taihei to avoid worrying others. Unaware that Koichiro's shop had moved from Tokyo to Hamamatsu, she searched Tokyo's eateries for him. She later reunited with him during a trip to Hokkaido when Taihei asked him to return home.

Among the characters involved with Umaru, Nana is one of the few who does not know about Umaru's secret identities (Himouto and UMR).

Nana is particularly popular among the characters, even being featured in special segments. She ranked first in the "Character Popularity Poll." Starting December 7, 2015, a spin-off manga titled "Akita Imouto! Ebina-chan," featuring her as the protagonist, began serialization on Nico Nico Seiga and "Tonari no Young Jump," with tankobon volumes also released. The series revealed that her favorite food is damako (rice dumplings).