Mr. Plankton — Characters & Cast

Initially seeks biological answers to justify his existence; evolves into wanting to experience true happiness and love with Jae-mi in his final days.

Begins as a cynical, reckless fixer hiding loneliness behind bravado. After learning he is terminally ill, he kidnaps Jae-mi to hunt for his biological father. By the end, he lets go of resentment toward his origins, accepts his non-biological father, and admits his deep desire to live and love fully before dying in peace.

Driven by a lifelong dream to become a mother and build a home; evolves into recognizing her own intrinsic worth without needing to fulfill traditional maternal roles.

Raised in orphanages and starved for familial belonging, Jae-mi tries to secure stability by pretending to be pregnant to marry into the traditional Eo family. After being jilted by Hae-jo, she gradually drops her defensive screaming and lies, confronting her diagnosis of premature menopause and embracing her true self.

Starts out wanting to protect Jae-mi and fulfill his family duty; evolves into pursuing genuine independence and self-discovery.

The gentle, sheltered 18th-generation sole male heir of the traditional Eo clan raised under his mother's strict thumb. When Jae-mi is taken, he breaks out of his passive nature, pursues them, stands up to his mother, and eventually lets Jae-mi go so she can follow her true feelings.

Preserving the ancient Eo clan lineage, reputation, and business.

The head of a 500-year-old clan who enforces rigid rules regarding bloodlines. Though formidable, her love for her son Eo Heung eventually forces her to accept his decision to seek his own path outside clan expectations.

Survival, money, and unwavering allegiance to Hae-jo.

Hae-jo's sidekick at the errand center who gets entangled in mob debts and wild chases. Despite his chaotic nature, his deep affection and loyalty to Hae-jo shine through as he supports Hae-jo's final wishes.