Ebina is a pale-skinned girl with cherry-brown hair that is tied in pigtails, she has cherry-brown eyes too. She is typically seen wearing her school uniform which is a white blouse, a red skirt, and a red bow which she pairs with socks pulled up to her calves and brown shoes. When outside of school, she wears skirts, blouses and other modern clothes worn by a teenage girl. Ebina often appears red in the face, along with steam rising on top of her head when nervous.
She has long cherry brown hair kept loosely in pigtails with red and white striped hair ties, which resemble little shrimps ('ebi'). Ebina has downward-pointing, eyes that match her hair color.
Ebina is a teenage girl who lacks self confidence and is very shy in nature. She sometimes stammers and blushes when talking to Taihei Doma or other small groups of friends. However, despite her lack of self confidence, she is a very optimistic girl.
Ebina is originally from Akita prefecture, which is in Northeastern Japan and is known for its agricultural industry. A year before moving to Tokyo and meeting Umaru Doma and Taihei Doma, she lived at home with her parents in the countryside. In a flashback scene, she is shown speaking to her parents over dinner with an Akita dialect and wears a thick jacket due to the harsh winters there. It is implied that she decided to go to school in Tokyo to find her brother after he left to find a job in Tokyo 10 years before. She mentions that she had to study hard to cover up her Akita dialect and buy trendy modern clothing to blend in with the people of Tokyo, instead of looking and sounding like a girl from the countryside. As such, she usually speaks standard Japanese around everyone, though her Akita dialect sometimes comes out when she is excited about food or worried that she might fail school and be sent back home to Akita.
Ebina lives alone, and it is noted that her apartment is directly below Umaru and Taihei. One day, she visited Umaru at her house and upon being introduced to Taihei, she noticed him looking at her eyes rather than her chest, which gave her the impression of him being a kind man. She developed a crush on Taihei ever since that incident and often gets flustered while talking to him.
It is implied that she has strong feelings for Taihei, due to his kindness. He was the first person to welcome her and look her in the eyes rather than staring at her chest when she arrived in Tokyo. She also mentions that he somewhat resembles her older brother when she first met him. Ebina loves necolumbus.
She enjoys eating and has a rather large appetite, though she becomes self-conscious when eating around Umaru and Taihei. When Taihei invites her to lunch with him and Umaru, he is surprised to hear that it was her first time eating at a family restaurant. She further proves this when she mistakes the small cup used for discarded clam shells as a small serving bowl. She explains that growing up Akita, she usually cooked at home. When she and the other girls visit NcDonalds, she ends up ordering several burgers for herself. She becomes rather embarrassed when Kirie pointed out that each burger has over 500 calories. When the girls have a study session, Umaru suggests that she imagine something she likes to make her feel less nervous. Her thoughts lead her to imagine her classmates' heads as food, before they all transform into Taihei. When she met Slyphine for the first time and was challenged by her, the only thing she thought she was best at was eating akitakomachi rice.
- The name Nana means "vegetables, greens" (菜).
- Nana's surname Ebina means "shrimp, prawn" (海老) (ebi) and "name, noted, distinguished, reputation" (名) (na).
- In Episode 9, Ebina made chocolate for Taihei Doma, but ate it after finding out that he's not very fond of chocolates.
- Ebina's lack of self-confidence is the result of her constantly failing miserably in school and in sports.
- As a result of her being voted the series' most popular character (apparently due to her level of cuteness and optimism), Ebina now has her own spin-off manga, "Akita Imokko! Ebina-chan" (Akita Native Little Sister! Ebina-chan a.k.a. Akita Sister! Ebina-chan.)