Yu Ji-an

He has a great physique, is almost always impeccably dressed, and is usually always alert to any trace of infidelity.
His body is literally like that of a professional athlete. Any clothes fit him perfectly.

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Yu Ji-an (known by the codename Sev) is the protagonist of the action-comedy manhwa The Retired Killer Wants a Quiet Life. He is a legendary S-rank assassin who used to work for a secret government organization called Rest.Yu Ji-an's Story:
• Life as "Sev": For 20 years, Ji-an lived in the underworld as a ruthless killing machine. He became the youngest agent to reach the impressive milestone of 300 successful missions.• The Desire for Retirement: Tired of the violence and blood, Ji-an's biggest dream was simply to retire and live a normal, peaceful, and ordinary life—what he calls his "healing bucket list."• The Golden Rule: Upon gaining his hard-earned freedom, he sets a primary goal for his fresh start: to earn money honestly and fairly, without taking anyone's life. He decides to take on ordinary everyday jobs, working as a convenience store clerk and a hotel employee.
The Central Conflict:The humor and action of the story revolve around the irony of his new routine. For an assassin who knows how to defuse bombs and take down entire armies, dealing with difficult customers, customer service tasks, and the rules of formal employment proves to be much harder than his old espionage missions.
Furthermore, his past refuses to leave him in peace. Local gangsters, suspicious figures, and underworld troubles constantly cross his path in an attempt to ruin his routine. Yu Ji-an must use his extraordinary combat skills covertly to deal with these threats, going out of his way to avoid breaking his promise to keep his hands clean and protect his hard-won normal life.

After completing 300 successful missions, he could retire and work as an assistant at a snack shop. He only retired because that type of work as a professional assassin never suited his "style". He himself had said so.
From childhood he was trained to be an assassin. He lived on the streets, abandoned by his parents at a young age, but after a few days, he was captured by people who turned him into a assassin

Yu Ji-an's personality is marked by the comical contrast between his ruthless killer instinct and his genuine desire to be an exemplary citizen.

His main traits include:

• Naive and Obsessed with Normality: Ji-an is extremely focused on his "healing bucket list." He takes the rules of everyday life completely literally, which makes him somewhat naive about how the real world works. He takes immense pride in simple things, like receiving his first honest paycheck or punching the time clock exactly on time.
• Professional and Dedicated: No matter the job—whether cleaning hotel bathrooms or stocking shelves at a convenience store—he applies the exact same discipline, seriousness, and perfectionism he used in his S-rank assassination missions.
• Calm yet Terrifying: In his daily life, he tries to be polite, kind, and smiling with customers. However, when provoked or when criminals threaten his peace, his killer aura instantly resurfaces. He can neutralize threats with a terrifying coldness, often maintaining a completely blank expression or a cynical smile while wiping out an entire gang.
• Pragmatic and Efficient: He dislikes wasting energy or drawing unnecessary attention. His solutions to everyday problems are often hilarious because he thinks like a military strategist just to resolve simple workplace drama.

— He is quite kind and gentle when it comes to the everyday things he worked 'hard' to achieve. He is kind and very attentive to what he does as a worker, living the normal life he so desired, a bit clumsy and too serious in terms of simple work as a shop assistant. But this kindness and attentiveness changes instantly to a killer and calm coolness, when there is a disturbance in the balance that he so carefully managed to achieve.
He is quite clumsy when it comes to a normal life, partly because he's been accustomed for a long time to being a secretive professional assassin, and everything he does, he takes too seriously.