Karuo Karube presides over Alexander, a bustling café-bar in Yanagihara frequented by regulars like Shūsuke Chitose and Kakeru Ohtori. Known for his womanizing tendencies, he cultivates a mentorship dynamic with Shūsuke, often peppering conversations with playfully suggestive banter that staff endure despite its occasional edge. His charisma blends gregarious humor with a theatrical flair for melodramatic antics, particularly when flirting with female patrons or employees. Yet beneath the boisterous exterior lies a warm approachability, earning him the loyalty of his team, who value his lighthearted leadership.

Karuo’s past as an unapologetic socialite contrasts with his current trajectory: an engagement to his pregnant girlfriend forces a reluctant pivot toward domesticity. Though he resists fully relinquishing his libertine identity, this looming commitment hints at gradual maturation, tempering his free-spirited persona with familial duty.

Within the café’s orbit, he weaves through pivotal moments involving Shūsuke and others, anchoring both comic interludes and narrative turning points. Exchanges with figures like Eriko Hino and Kinako Mochizuki expose his roguish charm and genuine camaraderie, framing him as a layered figure within the series' ensemble.