Juri Katou is a ten year old girl and a student at the same school as Takato Matsuki, Hirokazu Shioda, and Kenta Kitagawa. Her family owns a small tavern in the Shibuya district, where she sometimes works as a waitress and helps her father manage unruly customers. She lives with her father, Masahiko Katou, who is kind-hearted but very strict due to struggling to raise her properly after the death of her wife; her stepmother, Shizue; and her younger brother, Tadashi.

Initially, Juri is consistently presented as a cheerful and sweet person, always ready to cheer up her friends, and she is often seen carrying a puppet. Takato shows a strong attraction to her throughout the series.

Deep down, Juri's motivations stem from a desire for connection and to escape from her hidden sadness. She had secretly been playing the Digimon card game, and when the adventures involving real Digimon begin, she persistently seeks a partner of her own. She first tries to befriend Calumon and later meets Leomon. While Leomon initially tries to avoid her, he eventually decides to protect her from the Deva Kumbhiramon, at which point he transforms into her partner Digimon. She affectionately calls Leomon her prince.

Juri's role in the story becomes critical during the battle against Beelzemon. When Leomon is killed, she falls into utter despair, crying out that this was her destiny. Her intense negative emotions catch the attention of the D-Reaper, a digital entity that enters her body to feed on her feelings. After returning to the real world, she is absorbed by the D-Reaper, which creates a replica of her to take her place. She is eventually rescued by Takato in the form of Gallantmon Crimson Mode. Through this experience, she recovers from her depression and comes to understand that every person has the power to forge their own destiny.

Key relationships define her character arc. Her bond with her partner, Leomon, is one of admiration and dependency, making his death a devastating trauma. Her relationship with Takato Matsuki evolves from friendship to a deeper connection as he becomes her rescuer and a source of support in her darkest moment. Her family dynamic, including the loss of her mother and the subsequent pressures of her home life, contributes significantly to the vulnerability and hidden pain beneath her cheerful exterior.

Juri does not possess notable combat abilities like a traditional Digimon Tamer. Her primary strength lies in her emotional resilience and her capacity for empathy, even if that sensitivity ultimately becomes a vulnerability exploited by the D-Reaper. Her most significant ability within the plot is her emotional state itself, as her profound despair serves as the catalyst for the D- Reaper's invasion of the real world.