Matsuri is a very cheerful and optimistic girl, often thinking positively and trying to make friends with others; she also always attempts to talk things out with people rather than fight them, and often attempts to dissuade her friends from fighting with others; for example, stopping Arisa from beating up people and attempting to stop her from challenging Suzune to a duel to the death.
Matsuri is also very forgiving, as seen with Suzune — who killed many magical girls to prevent the births of witches — and Kagari — who crafted a revenge gambit to make Suzune's life miserable, and was indirectly responsible for the deaths of all the magical girls Suzune killed.
Not much is known of Matsuri's home-life. She had a sister, Kagari Hinata, an unnamed father, and a caretaker named Tsubaki Mikoto. Not much is given on how Matsuri relates to her family before the events of Suzune.
Matsuri used to be blind. It is unknown if she was born blind or how she handled her blindness.
Tsubaki often visited Matsuri's home, taking care of her and Kagari, and often told them stories. Tsubaki disappeared one day (due to becoming a witch), leaving the twins saddened, and Kagari also enraged. When approached by Kyubey after the disappearance of Tsubaki, Matsuri almost immediately wished to be able to see. The three began to search the town for Tsubaki, but failed to find her; however, they did find Suzune, after following the sound of the bell on the pendant that she was wearing - a pendant that originally belonged to Tsubaki. Kagari was confused by Suzune wearing Tsubaki's pendant, and apparently went home sometime after this discovery; Matsuri, however, followed Suzune to where she was hiding in despair near a house, and asked to become friends with her.
At some point after this, Kagari, now a magical girl, confronted Matsuri and erased her memories of Suzune as a part of her revenge gambit. Despite this, Suzune would later transfer into the same school and class that Matsuri attended.
As Matsuri makes no mentions nor allusions to Kagari during the story before volume 3, it can be inferred Kagari also erased herself from Matsuri's memory; the same can be said for memories of Tsubaki. It can also be inferred that Matsuri's father had his memories erased as well.