Souhei Fujii enters Yuki’s life as a transfer student in fourth grade, forging an unexpected bond with her despite early clashes. Raised in a single-parent household, he wrestles with displacement after his mother’s remarriage and pregnancy, sparking his urge to flee and live independently—a plan inspired by his admiration for lone wolves. Intrigued by Yuki’s peculiar animal-like scent, he inadvertently drives her to evade him to protect her secret. Their confrontation culminates in her accidental transformation, which scars his ear. Souhei deflects suspicion by claiming a wild wolf caused the injury, prioritizing her safety over his own.

As their trust deepens, he emerges as Yuki’s steadfast ally. During a storm two years later, their shared yearning to escape societal pressures surfaces, with Souhei confessing feelings of familial neglect. This vulnerability prompts Yuki to unveil her true nature. He meets her revelation with composed acceptance, acknowledging his long-held suspicions and pledging eternal secrecy. His unwavering support becomes a cornerstone of her struggle to reconcile her dual identity.

Defined by quiet resilience and an unyielding sense of justice, Souhei consistently prioritizes others’ welfare. His aspirations to become a boxer or wrestler reflect his pursuit of self-reliance, echoing his lone wolf ideals. Despite familial estrangement, he radiates gentleness and empathy, refusing to define others by hidden truths. His dynamic with Yuki thrives on reciprocity: he guards her secret while gently urging her to claim her humanity.

His presence proves pivotal in Yuki’s choice to embrace life as a human, their friendship symbolizing mutual acceptance. Through Souhei’s journey—marked by solitude, strained family ties, and a quest for independence—the narrative delves into themes of identity, belonging, and the fragile balance between connection and self-preservation.