Reika Ross, born Reika Ryūzaki, dominates as Nishi High School's top tennis player. Nationally renowned for an elegant playing style that earned her the "Madame Butterfly" moniker, her status is further elevated as the daughter of the Japanese Tennis Federation president, initially fostering an elite and haughty demeanor. Admired school-wide, she serves as a role model for peers like protagonist Hiromi Oka.

Reika initially maintains a cool distance, harboring jealousy toward Hiromi over new coach Jin Munakata's focus on the younger player's potential—complicated by Reika's own unspoken feelings for Munakata. Her early interactions with Hiromi carry subtle disdain, casting her as a rival. She leads senior players in ostracizing Hiromi, reflecting her initial refusal to acknowledge newcomers as equals.

Following Munakata's death, Reika's perspective shifts, thawing her icy exterior. She evolves from distant idol to supportive upperclassman, ultimately forming a crucial doubles partnership with Hiromi for major tournaments. This collaboration signifies mutual respect and Reika's acceptance of Hiromi's growth. Her rivalry with fellow top player Ranko Midorikawa—Munakata's half-sister—likewise matures into a respectful friendship, underscoring her emotional development.

In later narratives and OVA sequels, Reika fully embraces her role as Hiromi's mentor and ally. She acknowledges Hiromi's surpassing skills without resentment, focusing on her own legacy and contributions to tennis. Her refined image is reinforced by interests in classical music, including piano. By the series' conclusion, Reika embodies grace under pressure, having navigated personal and competitive challenges to emerge as a resilient and respected figure in the sport.