S Line — Characters & Cast

Initially driven to solve murder cases, his motivation shifts to protecting his niece Seon-a and exposing the origin of the glasses.

Ji-wook begins as an attractive, free-spirited detective whose head is covered in dozens of S Lines. When he puts on the glasses to solve local crimes, his cynicism collapses into despair as he discovers that his own family hides horrific secrets, driving him into a psychological breakdown.

Escaping her isolation and seeking a quiet, normal existence free from judgment.

Born with the ability to see S Lines without glasses, Hyun-heup grew up traumatized as a reclusive shut-in. Pulled back into society by a series of murders, she survives a tragic confrontation and transitions from a victim of her vision to the catalyst for global revelation.

Forcing absolute moral exposure on society and bringing about a global "rebirth".

Introduced as a reserved high school teacher with zero S Lines above her head, she is later unmasked as the mastermind behind the glasses. She views the S Line phenomenon as a divine gift meant to cleanse human hypocrisy.

Desperation for self-preservation, dignity, and revenge against bullies.

Ji-wook’s niece and Hyun-heup’s classmate who suffers severe bullying. After finding a pair of glasses, she attempts to gain leverage over her tormentors, but her story turns tragic when she falls from the school roof into a coma, prompting the core investigation.