Mika is a voluptuous adolescent with long, blonde hair with bangs that are tied in two geometrical pigtails and blue eyes. Her attire is a blue and white lingerié-like leotard with ruffles around areas such as the collar, the sleeves, and the leg-holes, wrestling boots with white stalkings and a white bustier with blue hearts on both bosoms.
Her attire is meant to be flamboyant, so she can stand out from the more experienced wrestling pools and circles. Being a Japanese blonde has its way of hiding her devotion and sincerity to her sport, as does her blue mask-band, and she possibly aims for making her arm joints less constricted due to the exposed portions of her uniform around her elbows, shoulders, breasts and buttocks. Her outfit is considered to be one of the most revealing designs of all the series' playable female characters.
In Street Fighter V, her appearance remains largely the same, with minor modifications to her outfit. She has notably matured, having a bigger bust and bulking up in muscle considerably, She retains the same colors except the blue hearts on her chest were removed with a new white, heart-shaped bustier. Because of the shift from sprites to 3D models, her pigtails are animated more realistically. She has two alternate costumes in the game; the first is a blue wrestling suit with a single long sleeve identical to Zangief's first alternate costume, and the other is her primary outfit modified in a phoenix motif with different shades of red and phoenix feathered design on her wrestling mask.
Mika is a sprightly, beautiful girl who prides herself on going all out and wowing the crowds with her wrestling moves. Her performances can be a little rough around the edges, but she definitely has the potential to enter the pro circuit. She idolizes Zangief and considers his way of fighting as the ideal route for herself. The mask she wears around her eyes can sometimes make it difficult to tell what Mika is thinking or feeling, but she is very open about her emotions and speaks in a distinctive manner.
After graduation from a local junior high school, a woman by the name of Mika Nanakawa begins her plans to become a female wrestler as the pupil of Yoko Harmageddon. By way of a several year-interval training periods, Rainbow Mika was ready to make her debut as a pro wrestler. She thought of the perfect marketing gimmick to promote her name—traveling the world and engaging in random matches with street fighters.
Street Fighter Alpha 3
Through this publicity journey, R. Mika meets the great Zangief and cooperates in some way with his mission to destroy the Psyco Drive, though they end up rescuing people with E. Honda as well (especially noted in AAC). Afterwards, Mika continues to train as a pro wrestler so that she can finally meet him (Zangief) again later on.
At some point in the story, Mika meets Karin, and the two fight. Karin is so impressed with Mika’s fighting ability that she promised that the Kanzuki Zaibatsu would become her sponsor if/when she becomes a first-class wrestler. Six months after the Psycho Drive was destroyed, Zangief finally met R. Mika at her home stage for a public bout. In just under 20 minutes, Zangief finally wins the match against Mika with a Final Atomic Buster; despite the devastating loss, she still has nothing but respect for him afterward. Zangief remarks that she's got a high wall to climb, but she is well underway.
Karin's sponsoring R. Mika is confirmed in Street Fighter Eternal, since Mika did later on become a reputable pro wrestler.
Street Fighter V
R. Mika returns in Street Fighter V, making her first playable appearance since her debut in Alpha 3. By her quotes, it is confirmed that Karin is still her sponsor.
Prologue: Kindred Muscle Spirit
R. Mika met with Zangief in London, much to her excitement, and the two fought to show each other's progress; as she expressed her admiration towards the Russian fighter, he, praising her skills, suggested that she follows him in his quest around the world to find "Muscle Spirit". She didn't know what that is but eagerly accepted. During a pause in India, Mika found Birdie stealing donuts, and stopped him. After overpowering the thug, she told him he wasn't nearly Zangief's equal and he had no Muscle Spirit; when he said he didn't understand what she was talking about, Mika realized to her confusion she didn't really know either, and Birdie took advantage of it to slip away, much to her irritation.
In Russia, Zangief got Mika to fight Laura, then he stepped in for a match of his own. Mika looked on with admiration, but after a while, she realized that the bear had gotten loose; not wanting him to spoil the fight, and wishing to protect her idol for a change, she stepped in and grappled with him. As she was at the end of her rope, Zangief came to help and dispatched the beast, to which she felt that she was more distant than ever from her objective. Mika told the Russian wrestler that she felt that she hadn't advanced yet enough, but Zangief disagreed, saying that by fearlessly facing the bear she showed Muscle Spirit - the fusion between the physical effort and the passion of the spirit. He then told her that by following in his quest she had earned the right to be his partner and fight by his side, much to her happiness.
After that, Mika met Ibuki at the Kanzuki Estate; the meeting, however, degenerated as Mika found Ibuki arrogant and not even willing to listen to her offer of " building some muscle",and Ibuki calling Mika bossy and finding her overexcited, and as a result, they prepared to fight.
Mika is also in Dhalsim's character story.
A Shadow Falls
In the game's main story, R. Mika teams up with her idol Zangief against Laura and Alex until the match is suspended due to the activation of the seven Black Moons created by Shadaloo. R. Mika later seen in the Kanzuki Estate having arguments with Ibuki (the same scene happened in the end of her prologue story). When Karin defeats Marz, she tells them that she will confidently join their fray in satisfactory if they continue to argue causing both to stop arguing and they disagree stating that they are satisfied.During the infiltration, both continue to argue until they are confronted by Balrog and Ed. Ibuki tries her best to beat Balrog with ninjutsu skills but failed as R. Mika does the same but to no effect. When Ed attempts to use Psycho Powers, Ibuki uses a smoke bomb to distract him long enough to get the chess piece as her and R. Mika to be reunited with Karin and Shibazaki. When both are now escaping, they watched Zangief pulverizes a brainwashed Abel with his Spinning Pile Driver as R. Mika idolizes him while Ibuki was disgusted on his acts.
In the final assault against Shadaloo, both R. Mika and Ibuki watch Zangief who manages to take down Satsuki one of the Dolls controlled by F.A.N.G after surviving Satsuki's sword slash from her Murasame. R. Mika is last seen with the other fighters watch Shadaloo's destruction.
- Nanakawa in kanji means "seven rivers," and her first name Mika means roughly "beautiful blossom".
- In Japan, R. Mika ends most of her sentences with "-ssu".
- R. Mika is the only playable female wrestler in the Street Fighter series.
- The All About Street Fighter Zero 3 guidebook states that R. Mika's hobbies are running on sandy beaches, push-ups, and wrestler's bridge. It also states that her special skill is gluttony.
- R. Mika shares the same birthday with Sakura.
- R. Mika's attire appears as a Swap Costume for Tekken character Kuma in Street Fighter X Tekken.
- Junko Takeuchi, R. Mika's voice actress in Street Fighter Alpha 3, is known for voicing the protagonist Naruto Uzumaki in the original Japanese language version of the Naruto and Shippuden anime, even though her role as R. Mika predates it.
- Mika's blue eyes are likely due to contact lenses. In her alternate colors, her eyes always match the color of her outfit.
- According to Street Fighter producer Yoshinori Ono, he really wanted R. Mika in Street Fighter IV but his boss wouldn't let him, saying that she "won't fit" in the game.
- Despite Street Fighter V already having a wrestling ring stage, (Ring of Destiny, from Capcom's 2016 Pro Tour tournament), R. Mika apparently has an unused wrestling level shown within her own official character artwork. This stage can also be seen briefly in the A Shadow Falls story mode, albeit only for a few cutscenes with Mika, Zangief, Laura, and Alex making small entrances. But other than a few Segways, it cannot be used or seen anywhere else. It's also noted it is, in fact, a different stage than the Ring of Destiny itself, as the overall structure of Mika's version is smaller in scale, and her name is held along signs all throughout the arena. Don Sauvage also makes a cameo in the unknown ring stage during the story mode.