In the Japanese version, she is voiced by Fumiko Orikasa.
At age 3, Rika was a little girl with fair skin, purple eyes, and ginger shoulder-length hair worn up in a ponytail held by a blue hair tie. She wore a yellow shirt with long sleeves and a white button in the chest, a blue dress, bloomers of undetermined color, white socks, and red shoes with white soles.
By autumn, 2000, Rika is much taller. She wears a dark green shirt with a broken skull and crossbones design in the front, a black jacket with a pocket on each side, short button-fly blue jeans, black socks, blueish gray and white steel-toed sneakers, and buckles around her waist and leg.
In 2001, Rika is described as "beautiful" by Coco. She wears a turquoise-turtlenecked T-shirt with a broken heart on the front, with short button-fly blue jeans, red wrist bands, white socks, red steel-toed sneakers, and buckles around her waist and leg. She usually wears her D-Power and a card case on her belt. When entering a Digital Field, she protects her eyes with sunglasses with blue oval-shaped lens.
Rika's school uniform is a white buttoned shirt, under a gray buttoned jacket with the Kagurazaka Girls' Academy's crest, a golden harp in a brown background, in the left side of the chest and a pocket on each side, a black skirt, black socks, and white shoes. When going to school she wears black shoes instead.
When fighting a Lynxmon, she wears a gray coat over her clothes.
When dressing up for a camera test, she takes her ponytail down and wears a pink and white frilly dress with buttons in the chest and multiple white ribbons on it, a white hat filled with flowers and two pink ribbons, white socks, and blue and gray sneakers. The dress is described as "beautiful" by Sugai. In the cover of Digimon Girls Festival, she wears a light blue and light pink version of this dress.
After returning to the Real World, Rika receives a new T-shirt with a full heart on the front.
In winter, Rika wears a light blue jacket with a white ruff in the neck, over her regular clothes.
In Digimon Ruki Dress Up, her underwear is a light blue strapless bra and lowleg panties, both with a white ribbon on them. She can also wear the clothes of Takato, Kazu, Kenta, and Suzie, as well as Henry and Jeri's shoes, and Rumiko's red and pink version of her top.
Rika's personality has evolved throughout the series. Initially, she was a merciless tamer seeking only to make her partner Digimon as strong as possible, and had a rough relationship with her mother. She would criticize and blame Renamon for their losses, and treat every other Digimon as her enemy, including Guilmon and Terriermon. Though she often covered up her true feelings with a tough girl act, she showed how she really cared about Renamon at the first few instances of Renamon's Digivolutions. During a fateful fight against Harpymon, Rika showed that she was willing to risk her own life to protect Renamon. After this fight, Rika began opening up to Takato and Henry as well. She still continues to throw her sarcastic remarks here and there and displays her annoyance to Kenta and Kazu's foolery. But she also cares about Jeri, motivating and comforting her at times of need. Of all the characters in the season, Rika has arguably shown the greatest change in personality.
In 2000, Rika was defeated by Ryo Akiyama in the Digimon Card Tournament. In autumn of the same year, she won the D-1 Grand prix without finding worthy opponents. In the same night, when she was bored, many gates to the Digital World opened in her room, and many Digimon wanted to become her Partner. However, she only wished for the strongest Digimon, and Renamon materialized in her room. Her victory in the tournament earned her the title of "Digimon Queen"
In 2001, Rika encounters Tamers Takato Matsuki and Henry Wong and their partners Digimon, Guilmon and Terriermon. However, she is initially unimpressed with the two boys, as Takato is an inexperienced Tamer and Henry prefers not to let his Digimon fight. Rika, who has been fighting Digimon who bio-emerge in the Real World with Renamon and having her load their data, longs for her partner to be the strongest Digimon in the world. Rika is frustrated by Renamon's inability to get stronger and Digivolve, even though she has loaded the data of many Digimon. When Renamon saves Rika from Dokugumon and is injured, Rika is distraught, and her caring for her partner causes Renamon to Digivolve to Kyubimon. However, she still cannot grasp that Digimon aren't just computer data. It isn't until she is kidnapped and held captive by IceDevimon, who wants to be her partner, that she realizes how cruel she had been to other Digimon. This event startles Rika, and once she is saved by Kyubimon and the other Tamers, she states that she hates Digimon and parts way with her partner. When Rika runs across Renamon fighting and uploading the data of three Flybeemon after their split, Rika becomes convinced that Renamon doesn't need her anymore. However, when a Harpymon bio-emerges and overpowers Renamon, Rika stabs Harpymon in the back to save her partner, as she has left her cards at home. Rika's actions cause Renamon to evolve and defeat Harpymon, but Kyubimon doesn't absorb her foe's data, no longer needing it to be stronger. Rika and Renamon's partnership resumes, stronger than ever, now that Rika realizes Renamon is not a tool, but a real friend. From this point on, Rika also becomes closer to Takato and Henry, as she is now able to appreciate their bonds with their Digimon.
With Takato, Henry and their partners on vacation in Okinawa, it was up to Rika and Renamon to keep the peace in Shinjuku as Digimon continued to appear at a rapid pace. When Digimon started appearing all over the world, Omnimon appeared to transport Rika and Kyubimon, along with Henry and Gargomon, to the battle site where Takato and Growlmon were fighting the true enemy: Mephistomon. Rika was present when the battle continued into an alternate dimension where the Tamers' Digimon combined their attacks to create the "Trinity Burst" attack to defeat Gulfmon and put a halt to the chaos in the Real World. Rika has a rough relationship with her mother; Rumiko is bubbly and upbeat, in sharp contrast to the aloof and sarcastic Rika. Rumiko wishes for Rika to be more feminine and sweet, which Rika resents. However, as she grows closer to Renamon and forms bonds with the other Tamers, she begins to realize how much she loves her family. Before the Tamers leave for the Digital World to rescue Calumon, Rika puts on a dress to make her mother happy before she leaves. She is unable to tell her mother about her upcoming departure, but her grandmother, who discovers Renamon's existence and dubs her Rika's "guardian angel", promises Rika that she will keep her departure to the Digital World secret from Rika's mother. Shortly after arriving in the Digital World, Rika, Renamon, Kazu and Kenta are separated from the others when they are sucked into a data stream. They stay with a friendly Jijimon and Babamon for a while, then leave to find their friends. When they get sucked into another data stream and arrive at a strange location, they have to fend against an attacking Megadramon until Ryo Akiyama and his partner Cyberdramon arrive and save them. Kazu and Kenta are excited to meet the famous "Digimon King", and Rika becomes bitter about his presence. After being reminded that she was just Ryo's runner-up, she and Renamon part with the boys and go their separate way. Later, Rika and Renamon find Calumon, and they reunite with the others. However, the canine Deva (Caturamon) captures Calumon and another data stream separates Takato, Henry and Terriermon from them until their fight with Beelzemon. When the Digimon Sovereigns send the Tamers to rescue Calumon, they meet Ryo and Cyberdramon again. Rika and Renamon climb down the crevice to the D-Reaper's dwelling alone, with Ryo and Cyberdramon at their heel. After retrieving Calumon, Rika and Renamon unite to stop the D-Reaper's bubbles from escaping, Biomerging into Sakuyamon in a display of true companionship and trust. Later, Janyu Wong sends the Tamers an Ark that will take the children home. However, Renamon picks up Impmon's scent, and Rika and Renamon go out to search for him. They find him, worn and beaten, and bring him with them to the Ark, arriving in the nick of time. When the D-Reaper appears in the Real World, Rika is determined to save her home. Before she leaves to fight it, Rika's mother gives her daughter her blessings, and presents her with a gift: a new T-shirt, identical to her old one, with a full heart on it instead of a broken heart. From this point on, Rika wears this new T-shirt, a symbol of her mended relationship with her mother. Though initially the Tamers cannot Biomerge with their Digimon in the Real World, a mysterious girl and her Dobermon give them the ability to do so. During the final battle against the D-Reaper, Ryo, biomerged with Cyberdramon to form Justimon, asks Sakuyamon to lend him her energy in a bid to destroy the D-Reaper. Though she chastises him for being reckless, Rika trusts Ryo's judgement. Sakuyamon gives Justimon the last of her fighting energy to power him up; however, this plan fails. Ultimately, the D-Reaper is defeated, but the same program that pulled the D-Reaper back to the Digital World is now doing the same to the Tamers' Digimon. Rika and Renamon, now de-digivolved into Viximon, are forced to say a tearful goodbye.
Digimon Tamers The Movie: Battle of Adventurers
Rika walks in on her grandmother checking her email; Rika's mother is currently in Paris for a fashion-related engagement. Rika's grandmother is delighted by the playing V-Pet dog on the desktop computer screen. Rika, who is uninterested in the V-Pet fad, heads to her room; however, Renamon appears to inform her that a Digimon had just appeared. They arrive at a local oil plant at night, and Renamon commences to fight against Pteramon and absorb its data. However, following the fight, Renamon then informs Rika of her suspicions of this particular Pteramon's motives for attack. Rika, who is bored from having nothing to do while her mother is gone, tells Renamon to come with her to find something to do on the town; Rika comments that mothers aren't around when one needs them, but are not as desirable when they are around. Rika and Renamon digivolves into Kyuubimon battle BlueMeramon, who is erupting the water from the sewers. When they emerge from the confrontations victorious, the two duos are informed from the heavens by Omnimon (and, strangely enough, by Calumon, who has found his way back to Tokyo) that their help is needed, and they are teleported from view.
After battle from Gulfmon, Humans and Digimon return to the Real World in the middle of the sea, overjoyed that they've saved the world.
Digimon Tamers The Movie: Runaway Locomon
Rika's family and friends are planning a party for her and she is less than enthusiastic when Takato spills the beans to her, after suggesting they go cherry blossom watching together when they actually happened "later" as Rika describes. The appearance of Locomon calls her into action, along with Renamon, jumping onto one of Locomon's carriages with Takato. Taken over by a Parasimon which tricks her into attacking Takato and Renamon with memories of her father, Rika is freed when Guilmon destroys the Parasimon controlling her. She Biomerges with Renamon into Sakuyamon to help defeat the Parasimon invasion in Tokyo. Following their defeat, Rika attends her birthday party thrown by her friends, only to leave just after blowing the candles out and being asked to sing karaoke. Takato finds her watching the sunset but Renamon stops him from going to her, letting Rika be alone with the memories of her father.
- "Wait! You can't. Renamon!"
- "Renamon Walk all over him"
- "You Sound Lika A Broken Record"
- "Hm, I see do me a favor? Don't tell anyone."
- Biomerge Activate.