Sakata’s older brother emerges as a secondary antagonist recruited by Sakata to challenge Ashiya Ashibe and his pet seal Goma-chan, motivated by envy over Ashibe’s popularity. Though initially deployed to intimidate Ashibe’s group, his menacing posture falters when repeatedly disarmed by Goma-chan’s endearing antics, forcing Sakata to repeatedly steer him back toward hostility.

His confrontations pivot on a juxtaposition of brute physicality and unexpected vulnerability. The tension he incites dissolves through Ashibe’s "Brotherly Love Hold"—a tactical embrace that defuses aggression by triggering affectionate memories, ensuring conflicts conclude with laughter rather than violence. This recurring dynamic cements his role as a comedic foil whose bluster masks a pliable, sentiment-driven nature.

His narrative presence remains episodic, limited to scenarios where his half-hearted antagonism underscores themes of rivalry tempered by empathy. No name, distinct physical traits, or extended backstory are specified, anchoring him solely to his function as a transient obstacle overcome through camaraderie.