Nanako is the young daughter of Ryotaro Dojima. Her mother, Chisato, passed away and her father is often busy with work, leaving Nanako home by herself. After the protagonist's arrival in Inaba, he begins bonding with Nanako as he returns to the Dojima house each day and finds her sitting on a cushion near the TV. She begins calling him her big brother and they become a part of one another's lives. Occasionally, the protagonist brings Nanako along when he hangs out with his friends who all come to know her and also treat her like a younger sibling.
Nanako is portrayed as a fairly innocuous and well-behaved child. Like many children, she speaks using her name as her pronoun. She loves Junes and is delighted whenever the commercial comes on. When the girls on the Investigation Team make terrible omelettes, she tries all of them and graciously calls all of them delicious. And through her Social Link, she opens up to the protagonist about the distance between her and her father.
Nanako has brown hair, parted into small pigtails with ribbons. In Persona 4, she always wears pink and white, such as a three color pink dress with a white turtleneck in winter, and a white sundress with pink ribbons in summer. In Persona 4 Dancing, Nanako gets to dance with Kanami Mashita and wears a yellow outfit and apron similar to hers.
Nanako is one of the unlockable selectable avatars for the pachinko machine. When selected, her mini-portrait will appears on the player's stat screen and she does the voice over for the machine's functions.
Trivia
While designing Nanako, Soejima was conscious of her role in the plot. He wanted the player to be concerned when something happened to her. Nanako's clothes ended up being fairly plain as Soejima imagined that Dojima bought all of them at Junes.[2]
One of Soejima's drafts for Nanako included a baseball cap and jeans, but he felt she looked too independent to bother coming home. He also tried giving her long hair, but it made her look like too much of a sheltered princess which did not fit as Dojima was not characterized as sheltering her.[3]
In her Persona Club P4 profile[4] and her Arena Ultimax remastered profile,[5] Nanako's favorite things are her dad, her older brother, Risette, everyone else in the Investigation Team, and Junes. She dislikes fighting and shiokara. Her special skill is singing the Junes jingle.
During the development of Persona 4 Arena, Arc System Works jokingly suggested adding Ryotaro Dojima as a playable character, with him summoning Nanako as his Persona. The idea was dropped as it likely would not have elicited a positive reaction from Atlus if presented.[6]
During Atlus's 35th anniversary knowledge test, the final question was, "What date did Nanako first call the protagonist her older brother?"
In the 2015 build for Persona 5, there is a model for a character who is assumed to be an older Nanako with longer pigtails and a down jacket that has "N. Dojima" written on it.[7]