TV-Series
Description
Retsu Seiba stands as one of the twin protagonists, instantly recognizable by his vibrant red hair, matching red eyes, and signature green hat, typically worn outside school or while sleeping. His distinct look includes a height of 124 cm and weight of 28 kg, with red dominating as his primary color theme across gloves, clothing, and his Mini 4WD cars. Early attire featured a white vest, red t-shirt, green shorts, and green-yellow shoes, later evolving into coordinated team uniforms during competitive phases.

Personality-wise, Retsu embodies patience, analytical thinking, and levelheadedness, forming a deliberate contrast to younger brother Go's impulsiveness. As the responsible sibling, he consistently exercises self-restraint and strategically assesses racing conditions, though occasional arguments with Go or flashes of annoyance at unreasonable behavior surface. His core racing principles firmly reject battle tactics or sabotage, advocating instead for fair competition centered on technical skill and teamwork.

His racing style prioritizes control and stability, excelling particularly in cornering maneuvers. Cars within his Sonic series—Sonic Saber, Vanguard Sonic, and Hurricane Sonic—shine through agility and smooth turns. The original Sonic Saber held deep sentimental value; its destruction in Dr. Ogami's volcanic lab caused significant emotional distress. Subsequent machines faithfully maintained the Sonic lineage's cornering specialization, evolving through models like Buster Sonic, Blitzer Sonic, and Great BlastSonic.

During childhood competitions, Retsu captained the TRF Victorys team in the Mini 4WD World Grand Prix (WGP), emphasizing team formations over individual racing. His leadership leveraged strategic race planning, balancing team coordination with technical adaptability. A notable tactic involved a calculated collaboration with Professor Ogami to develop Hurricane Sonic, exploiting Ogami's battle machine expertise without compromising Retsu's ethical racing principles.

In adulthood, Retsu pursued a career in space development engineering internationally. His contributions inspired the naming of a space probe after his Mini 4WD cars. This path, guided by Professor Tsuchiya, diverged from Go's journey as a professional racer. The brothers' "Let's Go Brothers" legacy continued through mentoring new racers, including Go's son Tsubasa.

Additional traits include hobbies like collecting postcards and playing games, blood type A, and an April 10 birthdate. A documented fear of ghosts appears in one storyline, presented within the narrative as a justified phobia.