Semantic Error — Characters & Cast

Initially: efficiency, fairness and the preservation of a life with no unpredictable inputs. This mutates into a need to understand the one variable he cannot resolve, and finally into the wish to keep that variable close — even though keeping it means accepting permanent unpredictability.

Introduced as the epitome of an inflexible, rule-abiding person: a computer science underclassman who prizes reason and a rigid sense of what is right above all else. Deleting his freeloading teammates' names is, to him, simple arithmetic. The consequences force him into sustained contact with someone he cannot categorize, and his arc is a slow decompression — wariness giving way to a lowered guard, then to a recognition of feelings he still struggles to accept. His transformation is not a personality transplant; he ends the series still precise, still principled, but no longer using precision as a wall.

Starts as wounded pride and the desire for proportional revenge; becomes fascination with the one person on campus immune to him; resolves into an unusually patient, careful persuasion — he wants to be chosen, not merely tolerated.

A Design department senior and campus star whose study-abroad plans are wrecked by Sang-woo's deletion. He begins as the aggressor, weaponizing his charisma to dismantle Sang-woo's routine. The pivot comes when he catches a glimpse of Sang-woo's human side and changes tactics from pranking to befriending — a shift he initially mistakes for a better strategy and only later understands as attachment. His arc runs from effortless popularity toward genuine investment, culminating in a decision about an offer to work in France that forces him to define what he actually wants rather than what is simply available.