Kurata Ohnami is the devoted butler to the aristocratic Asuka family. Initially appearing innocent and hapless, he assists the chained Jun Asuka under her parents' orders, performing intimate tasks like feeding her and aiding with bodily functions despite his visible embarrassment. His fierce loyalty emerges when he attempts to shield Jun from her aggressive suitor, Mauta Nandou, only to be physically overpowered until Jun intervenes.

When Jun flees her family’s arranged marriage tradition, Ohnami accompanies her. Their relationship shifts from a strict mistress-butler hierarchy to mutual companionship, with Jun proposing they interact simply as friends. During their escape to Tokyo, Ohnami displays jealousy as the charismatic relative Ryo Asuka charms Jun and whisks her away on city adventures.

Ohnami’s evolution peaks when Jun confesses her love at a hotel. Shedding hesitation and subservience, he finds the courage to reciprocate, leading to an intimate encounter where they consummate their bond. This act marks his transition from passive servant to equal partner, embodying the meaning of his name, "big-wave tanker," visualized by tidal wave imagery during their union.

In the anime, Ohnami supports Jun against the Golden Cherry Boys, enforcers sent by her mother. He inadvertently aids her during skirmishes and persists in rescuing her after her capture, ultimately running down the final assailant. Despite being easily subdued in fights, his unwavering dedication underscores his role as Jun’s emotional anchor rather than physical protector.

Across all portrayals, Ohnami’s journey traces his growth from a timid servant to a committed partner who wins Jun’s trust and affection through steadfast loyalty and emotional support, culminating in their joint decision to build a future together.