Kuroudo Marume, the fourth Gear Fighter recruited into the Tobita Club, stands as a pivotal member shaped by his multicultural roots. Born to a Japanese father and a half-Russian mother, his heritage manifests in striking blonde hair, piercing blue eyes, and fair skin. Childhood in France was marked by financial strain, where he bonded with Francoise, Jean, Pierre, and Lola. Together, they resisted their affluent rival Ritchie by restoring a discarded Crush Gear—the Shooting Mirage—equipping it with handcrafted wooden wheels to protect their playground, an effort that forged his enduring belief in resilience and collaboration.

A disciplined kendo practitioner, Kuroudo’s acute hearing allows him to dissect mechanical flaws in opposing Gears through sound, augmenting his tactical precision. Partnered with Kyousuke Jin in Team Griffon, their dominance earned them the title "The Dynamic Duo." Their alliance fractured when Kyousuke surreptitiously embedded a microchip in the Shooting Mirage to guarantee wins, driving Kuroudo to quit Gear Fighting, disillusioned by betrayal.

Relocating to Japan, he intervened when Kouya Marino and Jirou Oriza faced a bee attack, later directing them to Kyousuke for repairs. Despite unresolved tensions, he joined the Tobita Club, reigniting his commitment to teamwork. His growth involved confronting a crippling fear of failure, notably during a World Cup match against Kyousuke. Initially withdrawing, he later accepted vulnerability as a stepping stone, symbolizing his evolution by upgrading his Gear to the Shooting Phantom—a shift from dependence on old bonds to self-sufficient mastery.

Kuroudo’s relationships reflect loyalty and reconciliation. He maintained ties with his French companions across continents while cautiously rebuilding trust with Kyousuke through shared tournament trials. His strategic mind, often leveraging tactics inspired by *Romance of the Three Kingdoms*, proved instrumental in outthinking adversaries. Though intermittently haunted by self-doubt, his journey underscores conquering personal fears to solidify both individual tenacity and collective strength.