Hailing from an island near Nagasaki, Rin Namiki transfers to Asakusa in Tokyo fueled by her dream of jet racing. This ambition stems directly from her mother, Furuki Namiki, a legendary Jetter who perished in a racing accident. Rin enrolls at Asakusa Girls' High School as a new student to pursue this goal.

Rin possesses chin-length brown hair adorned with two signature clips: a blue triangle on the right and a yellow five-petal flower on the left. Her olive-green eyes mirror her mother's. Casually, she favors a dark pink sleeveless top. Her school uniform is a white shirt, red tie, blue skirt, white socks, and sneakers. For jet racing, she dons a bright orange and yellow wetsuit with teal and navy blue designs, always keeping her hair clips in place.

Energetic, polite, and fiercely determined, Rin embodies a genki girl spirit, especially about jet racing and forming connections. She frequently expresses excitement over new experiences and people, often commenting on how "cute" or "pretty" other girls are. This enthusiasm manifests in a lack of personal boundaries; she readily hugs, clings to arms, sniffs scents for recognition, and stands very close during interactions, particularly with her partner Misa Aoi. Academically, Rin struggles, failing a test for the first time and requiring intense library study sessions. She ultimately passed with an 85%, though the stress temporarily impacted her health.

Her Tokyo journey begins dramatically with a stolen bag, leading to a fateful meeting with Misa Aoi, who helps recover it. They become dorm roommates. Rin persistently encourages the reluctant Misa to form a jet racing team with her, founding the Jet Racing Club at their school. She recruits members like Kiriko through passionate persuasion, often sealing invitations with physical embraces.

Rin's story charts her growth as a Jetter and teammate. Early races reveal her inexperience—forgetting to use the boost function or misusing it before turns, leading to losses. Yet she remains a graceful loser, treating each race as a learning opportunity and openly admiring stronger rivals like Kaguya Shijyuin's team. Her perseverance and deepening bond with Misa gradually improve their coordination, culminating in winning the Kandagawa Cup. Rin also confronts emotional hurdles, revisiting her mother's legacy during a trip home and sharing her grief over the accident with Misa, strengthening their partnership.

In the OVA set after the Kandagawa Cup victory, Rin participates in creating jet racing promotional videos, demonstrating her ongoing passion for the sport and camaraderie with other teams. Activities include washing the team jet Orcano with Misa, focusing on lighthearted interactions.

The video game adaptation expands her storyline slightly. Rin and Misa defeat the Sea Serpents in the Kandagawa Cup finals but immediately challenge the team Dress to a showcase race. Depending on the story arc, Rin's team wins or loses specific races, such as a river wager bet against Dress in their rivals' arc. The game also features her as a rival to teams like Grindcore, whom they defeat in one narrative path, and includes the revelation about her mother's accident, reinforcing her emotional ties to jet racing.

Key relationships center on her foundational partnership with Misa Aoi, evolving from acquaintances to inseparable teammates through shared races, studying, and living together. Rin frequently initiates physical contact with Misa—hand-holding, cuddling, and enthusiastic hugs—viewing their meeting as fate. She admires Kiriko's studiousness in the library, hugging her to invite her to the club; regards Kaguya as a gorgeous and worthy rival; and connects broadly with racers like Hina Tsuruno or Fūka Tamaki through embraces and encouragement. Her hobby of painting is occasionally referenced. Etymologically, "Rin" (凛) means "dignified, severe, cold," while "Namiki" combines "wave, breaker" (波) and "yellow" (黄). Outside the primary series, she appears in a Senran Kagura crossover event as a guest character.