The protagonist's cousin and daughter of Ryotaro Dojima. She represents the Justice Arcana. Welcome home!
Overview
Nanako Dojima is the six-year-old daughter of Ryotaro Dojima and cousin of Persona 4 protagonist Souji Seta. Her mother died in a hit-and-run accident when she was in nursery school. Because her father is often out of the house, she learned some level of independence and can take care of herself when at home. Like many children her age, she frequently watches TV. She is also highly fascinated by Junes, a chain of large department stores with a branch in her small hometown of Inaba. She often sings along to the Junes advertising jingle when she hears it on television.
Social Link

Justice Arcana
Nanako's social link is that of the Justice Arcana. Over the course of her link, she becomes closer to not only the main character, but her father. Throughout the social link, the main character is trying to help Nanako understand her mothers death. She asks various questions such as "Why do people die?" and other questions regarding her mother. Nanako has an issue with her father, and has a hard time thinking that he loves her, 
Sraosha
and that she's his "Real daughter". At the end of the S.Link, the family is all united, as Nanako realises she loves her father, and her "Big bro". Nanako is one of the few Social Links that requires a certain statistic (Expression) to continue.
After completing Nanako's social link The Protagonist receives ability to create Sraosha of the Justice Arcana through the item "Family Photo".
The Midnight Channel
In early November of 2011, Nanako is kidnapped by the supposed serial killer that had been terrorizing Inaba and thrown into the TV World. There, her heart of hearts crafts a world based on how deeply she misses her mother: Heaven. Her life in danger, Souji and his friends rush to save her from her kidnapper, but the dense fog of the TV World is too much for her and she is hospitalized. At one point, her vital signs give out and she nearly dies, but she is called back by the sound of Teddie's voice and is able to fight her sickness until the fog in Inaba is eliminated with the defeat of Ameno-sagiri.
Voice
Nanako's voice acting is done by Karen Strassman in the English version, and Akemi Kanda in the Japanese version.