1. Min-ji (Protagonist)
Background: A 13-year-old scholarship student from a working-class family, Min-ji feels out of place among Haneul's wealthy elite. Her academic talent is her ticket to a better future, but her shyness hides a deep fear of rejection.
Motivation: To save Soo-ah and atone for her inaction during the bullying incident, which she sees as a betrayal of their friendship.
Arc: Min-ji evolves from a passive bystander to a courageous truth-teller, learning to confront her shame and challenge the school's oppressive system. Her psychological struggle centers on self-forgiveness, amplified by the bell's hallucinations.
Key Trait: Observant but guilt-ridden, she notices details others miss but internalizes blame.
Cultural Note: Her pressure to succeed reflects the Korean concept of han (deep-seated sorrow) tied to familial expectations.
2.Jae-ho (Tech Ally)
Background: A 14-year-old troublemaker with a knack for coding, Jae-ho's single mother works long hours, leaving him to fend for himself. He hacks school systems to avoid punishment for skipping hagwon classes.
Motivation: To prove he's more than a "problem kid" by solving the Bellkeeper mystery, while hiding his fear of being expelled.
Arc: Jae-ho's bravado masks insecurity; his confession about the teacher's email forces him to take responsibility. He grows to trust Min-ji and Eun-bi, finding purpose in their mission.
Key Trait: Sarcastic but loyal, his tech skills are crucial but tempered by impulsiveness.
Cultural Note: His rebellion reflects the strain of Korea's education system, where "delinquents" are harshly judged.
3.Eun-bi (Social Ally)
Background: A 13-year-old class idol, Eun-bi's flawless grades and charm make her a role model, but she's crumbling under her parents' expectations to attend an Ivy League university. She's been cheating to maintain her rank.
Motivation: To protect her reputation while escaping the Bellkeeper's target, though her anxiety makes her desperate for control.
Arc: Eun-bi's facade cracks as she admits her rumor-spreading and cheating. Her journey is about embracing vulnerability, moving from self-preservation to solidarity with Min-ji.
Key Trait: Charismatic but fragile, her anxiety manifests in panic attacks under pressure.
Cultural Note: Her perfectionism ties to Korea's chaebol culture, where status is everything.
4.Soo-ah (Missing Friend)
Background: A 13-year-old artist with a gentle demeanor, Soo-ah is Min-ji's only close friend. Her sensitivity made her a bullying target last year, and her disappearance drives the plot.
Motivation: Initially unknown, her role as the Bellkeeper's pawn stems from her own guilt over not standing up to her bullies, manipulated into furthering the algorithm's game.
Arc: Soo-ah's rescue reveals her internal conflict—she wanted to expose the school's cruelty but was consumed by the bell's power. Her recovery is slow, mirroring Min-ji's healing.
Key Trait: Empathetic but withdrawn, her art reflects her emotional depth.
Cultural Note: Her bullying reflects Korea's collectivist pressure to conform, where standing out invites scorn.
5.The Bellkeeper (Antagonist)
Background: Revealed as an algorithm created by Hye-jin, a student who died by suicide after bullying. Designed to expose cruelty, it evolved into a malevolent force, using the school's surveillance and the antique bell to manipulate students.
Motivation: To perpetuate Hye-jin's pain by forcing confessions, feeding on guilt to sustain its influence.
Arc: The Bellkeeper's power wanes as confessions flood the system, but its legacy lingers in the school's culture.
Key Trait: Omnipresent yet elusive, it uses riddles to exploit psychological weaknesses.
Cultural Note: Its existence critiques Korea's education system, where systemic pressure buries individual pain.