Operation Center is a domestic South Korean law enforcement/intelligence agency that mostly deals with cases related to North Korean attempts to infiltrate and conduct terror acts in South Korea.
- Badass in a Nice Suit: Almost all of the OP agents are this when they get into a gunfight.
- Government Agency of Fiction: It doesn't get any more obvious than this.
- Sharp-Dressed Man: This is the standard for OP agents (At least for the males).
- SWAT Team: The agency has a tac team to support its agents on the ground.
- Weapon of Choice: Most of the OP agents use Beretta 92FS pistols.
- For the tac teams, they use various Heckler & Koch MP5s.
An experienced OP agent responsible for handling the case of Lee Bang-Hee and the partner of Lee Jang-Gil, he is currently in a relationship with fish store owner and ex-alcoholic Lee Myung-Hyun.
- Deadpan Snarker: When a call comes to OP from Park, he wanted to speak to his "old friend". He takes it very well.
- Experienced Protagonist: A veteran agent with OP.
- Heroic BSoD: Has one when he finds out that Myung-Hyun is actually Bang-Hee.
- Improbable Weapon User: During the fight in the stadium control room, he uses a phone handle.
- It's Personal: He feels this towards Park after his partner was shot dead.
- It's Not You, It's My Enemies: The reason why Yu hasn't told his girlfriend about his real job. Ironically, she already knew about his real job because of her mole status for the North.
- It's Up to You: After Director Ko refuses to listen to his advice and his partner killed, he decides to head to the stadium and stop Park by himself.
- Quick Draw: He does this to Park by taking the sidearm from the stolen SWAT uniform he used.
- Spell My Name with an "S": Sometimes, his surname is "Ryu", which is not a proper Korean surname.
- The Lost Lenore: For the fake Myung-Hyun after he was forced to shoot her.
- The Mole: Suspected of being one. Averted when he learns that the fake Lee Myung-Hyun, his girlfriend, was the one who bugged the agency with bugs hidden inside the fishes she sold to them.
- "The Reason You Suck" Speech: During the stadium confrontation, he rants to Park that the cause of the Korean division was due to Kim Il-Sung's use of force that started the Korean War.
Another experienced OP agent and the partner of Yu-Jong Won, he is also assigned to handle the case of Lee Bang-Hee.
- Easily Forgiven: Jong-Won forgave him for bugging his car after he confessed to it, being that they were partners for a long time.
- Experienced Protagonist: A veteran agent with OP.
- Character Death: Gets killed by Mu-Young in an ambush while confronting the actual mole.
- Genre Savvy/Properly Paranoid: Decides to bug Jong-Won's car after they were informed of a possible mole working for the North Koreans. Turns out that he was wrong.
- He Knows Too Much: Was shot and killed after his confrontation with the mole because he's the only OP agent who can positively identify the person.
- It May Help You on Your Quest: The soccer ticket he got after the confrontation with the mole gave his partner the info he needed by figuring out that Park's team was after the stadium all along instead of ransom money and a plane out of Seoul.
- Redemption Equals Death: When he realizes that Jong-Won is not the mole responsible for leaking OP info to the North Koreans.Lee: I planted a bug in your car. Will you forgive me?
- Shipper on Deck: Is one for Jong-Won and Myung-Hyun and encourages him to propose to her when he can.Lee: When are you going to tell her?Yu: [Shakes his head to say no]Lee: You can't hide it forever.Yu: I don't wanna burden her.
- Tempting Fate: After he finds a bug in the fishes in the office, he decides to confront the real mole without waiting for help. This is what got him killed.
- The Mole: Suspected of being one. Averted when he learns that the fake Lee Myung-Hyun, Jong-Won's girlfriend, was the one who bugged the agency with bugs hidden inside the fishes she sold to them.
An OP agent who mostly stays in the office, rarely seen in the field. His colleagues call him "Oddball".
- Almighty Janitor: Despite being a trained OP field agent, all he did was odd jobs such as delivering mail and clean up the aquariums.
- Big Damn Heroes: He helps out by leading a OP tac team to take down Park in the stadium control room.
- Butt-Monkey: Gets teased by his colleagues and superiors for being easily scared. For one scene, he was thrown a plastic snake in order to scare him.
- Combat Pragmatist: Shoots Park at the back before he can use a wrench to clobber his colleague.
- Cowardly Lion: When he hears about a CTX demonstration about the requirements needed to make it detonate, he begins to scurry away from the room.
- Eureka Moment: While on security duty, Sik was able to figure out that the CTX was planted in the stadium since one of the stadium lights was turned on while the others were not since it held a daytime match.
- I Just Want to Be Badass: One interpretation on how Sik feels in his OP job as the Butt-Monkey to his colleagues and superiors.
- In-Series Nickname: He's called "oddball" many times.
- Took a Level in Badass: See Big Damn Heroes for more details.
The director of Operation Center, he's the superior of Jong-Won, Jang-Gil and Seong-Sik.
8th Special Forces Unit, Korean People's Army Ground Force
The 8th Special Forces Unit is an elite commando unit under the Korean People's Army Ground Forces division. As such, it is trained to conduct recon and sabotage attacks in South Korea in case of another Korean War in the peninsula.
- Better to Die than Be Killed: Presumably they use CTX in small explosive devices that they swallow in order to commit suicide in case they were about to be captured by South Korean law enforcement.
- Combat Pragmatist: They have no problems masquerading as fake South Korean soldiers and SWAT officers, use human shields, sneak up on their targets and snap their necks and bomb civilian targets.
- Dressing as the Enemy: The unit masqueraded as South Korean soldiers in order to secure the CTX. Also dressed up as SWAT officers by taking the actual uniforms and gear from the dead officers in the stadium.
- Elites Are More Glamorous: Given that they are a North Korean special forces unit.
- Far East Asian Terrorists: What they eventually become near the end of the movie.
- For a time, Park's team hijacked Flight 257.
- Identical-Looking Asians: The unit takes advantage of this by masquerading as ordinary South Koreans (and Japanese), which is Truth in Television.
- Rogue Agent: The unit was clearly acting against Pyongyang's orders since they had no problems killing their own officials in Seoul, being the Corrupt Politician that they are.Commander: No more corrupt politicians! No more 50 years of separation, disgrace and humiliation!
- Visionary Villain: The unit hopes to make history by reuniting the two Koreas from another war.Commander: We're writing a new history of Korea! And the beginning of it is in your hands!
- Training from Hell: Its prospective recruits are given brutal training as part of the KPA's protocol to have battle-hardened soldiers.
- Weapon of Choice: Ranging from Desert Eagles to Beretta 92FS pistols, including IMI Uzis.
- Well-Intentioned Extremist: They all want to reunify the divided Koreas again. But to do this, they needed to kill everyone in the stadium so that another Korean War can start.
- Why We Are Bummed Communism Fell: The unit was disillusioned with how their leaders aren't doing enough to help North Koreans survive or push through with unification plans with the south.
- Would Hurt a Child/Would Hit a Girl: Its operators have no qualms on using CTX bombs on women and children, if it helps to reunify Korea in the long term.
A career officer in the Korean People's Army Ground Force and the commanding officer of the unit, he's responsible for recruiting Lee Bang-Hee as the newest recruit.
- A Father to His Men: Struggles to ensure his unit is intact. When his men are killed, he takes it very, very personally.
- Authority Equals Asskicking: Is the head of his unit in Seoul. And he is also feared for his special forces skills.
- Big Bad: For the movie.
- Deadpan Snarker: He calls Yu his "old friend" when he made the call to OP.Park: I want to talk to my old friend.
- Determinator: Despite having a knife wound, he still continues to fight against Jong-Won. It took a gunshot at the back to put him down.
- Evil Mentor: He was Bang-Hee's training instructor who oversaw her training back in '92.
- Genre Savvy: When he needed to speak with Hee, he arranges to talk online in an internet cafe.
- Handguns: Uses an IMI Desert Eagle with a laser sight during the confrontation between him and Yu in downtown Seoul after his Beretta 92FS runs out of ammo.
- Hero Killer: Responsible for killing off several Korean SWAT and OP tac team operators. He's also responsible for killing Jang-Gil after he uncovers the fake Myung-Hyun as the real mole.
- Improbable Weapon User: During the fight in the stadium control room, he uses a phone handle and later a wrench.
- In the Back: He was shot and killed by Sik by firing his pistol at him.
- It's Personal: After he lost two men during a shootout with Korean SWAT units.
- Knife Nut: Carries one with him during the ambush on the convoy. He uses it gut the convoy's CO to death when his bluff was called.
- Villain Has a Point: While Park's actions are bad, he does have a point when he insists that his fellow North Koreans are having a hard time while South Koreans aren't doing much to help them alleviate their suffering.Park: Our people in the North are dying on the street. They barely manage to live with roots and barks. Our sons and daughters are being sold off... Have you ever seen parents eating the flesh of their dead kids? With cheese, Coke and hamburgers, you wouldn't know.
- The Dreaded: Partially this because of the civilians that got killed when he hijacked Flight 257.
- "The Reason You Suck" Speech: Gives him one during a phone call when South Koreans are just content to eat fast food while North Koreans are not having enough food to get by everyday. See Villain Has a Point.
- Worthy Opponent: See Jong-Won as one when they meet again after the hijacking of Flight 257 since he was able to stop his hijack scheme back then.
- You're Insane!: Jong-Won says this when he plans to detonate the final CTX bomb at the stadium to jumpstart another war.Yu: This is crazy!Park: Sometimes history needs craziness to help it.
The newest recruit to the unit. She was sent to South Korea to conduct a wave of terror attack against Seoul. She also assumed the identity of a sick girl named Lee Myung-Hyun.
- Cold Sniper: To OP and other South Korean law enforcement/intelligence agencies.
- Friendly Sniper: To her allies.
- Dark Action Girl: Maintained a very high body count during the 1990s.
- Dual Wielding: Her main tactic of choices when using sidearms.
- Even Evil Has Loved Ones: To the real Lee Myung-Hyun after she moved to Seoul.
- Sniper Rifle: Uses a Heckler & Koch MSG-90 as her main weapon after she resurfaces to assassinate Lim Bong-Ju.
- The Dreaded: South Korean law enforcement and intelligence agencies greatly fear her for her Cold Sniper and special forces training, being used to kill off several prominent South Korean VIPs in the 1990s.
- The Dragon: Is this to Park when he arrives in Seoul.
- The Smurfette Principle: One of two female commandos in Park's unit operating in Seoul.
- Walking Spoiler: Talking more about her would reveal things that are suppose to be kept secret. Especially when Jong-Won/the audience finds out that Bang-Hee has changed faces and identities.
An ex-alcoholic and the owner of a fish store, she's in a relationship with Yu Jong-Won. She's also the real Lee Bang-Hee after she went through plastic surgery in Japan.
- Assault Rifles: Uses a Steyr AUG A1 with a scope as her main weapon during the stadium raid.
- Becoming the Mask: What Park fears when he meets up with her again. He feared that her relationship with Jong-Won was not making her see things straight with their objectives.Park: When I met you here, I saw the confusion in you. Thanks to you, we lost two of our men!Bang-Hee: I did what I could do.Park: Yeah, you saved my life.Bang-Hee: What do you want?Park: You've changed.Bang-Hee: Of course I have. From Hee to Hyun.Park: Not only in appearance, but inside as well!
- Crazy-Prepared/Genre Savvy: She rigged her hideout with explosives in case of a raid. She uses it when OP tac teams raid her residence.
- Girl Next Door: Was one for the movie, being the store owner of a fish store.
- HeelFace Turn: As a result of Becoming the Mask, she decides to send a fax message to outline details on how to stop the bomb plot.
- In Love with the Mark: What happened the more she spent time with Jong-Won.
- Locked Out of the Loop: She doesn't know about Yu's actual job. In fact, she already knows for a long time.
- Love Redeems/Redemption Equals Death: Her fax message to Jong-Won indicated that she was in love with him and she wanted him to stop her from assassinating the South Korean President.
- Secret Test of Character: Park gives her a pistol without ammo to see if she'll commit suicide over her failures in order to test her allegiance. He realizes that she was still loyal to the unit's cause.
- Suicide by Cop: Decides to be killed by Yu after she aims her assault rifle at the South Korean President's limo rather than be arrested and have her ties to him revealed by the police.
- The Reveal: When Jong-Won finds out that she's Bang-Hee after tailing her due to being wounded in a previous shootout.
- Walking Spoiler: She is one for all story purposes. She's the actual mole responsible for bugging OP and for assassinating Bong-Ju.
An underground arms dealer turned OP informants, his assassination at the hands of Bang-Hee jumpstarted the movie's entire plot.
- Arms Dealer: What he does for a living.
- Character Death: Gets killed by Bang-Hee thanks to her Cold Sniper skills.
- Genre Savvy: When he called OP, he demanded to meet with their agents at a public place, knowing that someone's out to get him.
- Only in It for the Money: The reason why Bong-Ju did business with the 8th Special Forces so that he can profit from selling the CTX to them.
- Plot-Triggering Death: His assassination jumpstarts the entire plot when the agents look into his death, leading to the terror plot.
- Properly Paranoid: Bong-Ju wanted to meet with OP at a public place so that Bang-hee won't get him. It never worked.
- The Informant: Was one for OP after he decides to go to them.
- We Hardly Knew Ye: Nothing is know about him aside from his arms dealing business.
The actual Lee Myung-Hyun
The actual Lee Myung-Hyun was a young woman who was placed in Halla Hospital in Cheju Island due to Innate Immunodeficiency Syndrome.
- Girl Next Door: She was one before being sent to live in Halla Hospital.
- Ill Girl: Has been diagnosed with Innate Immunodeficiency Syndrome.
- Morality Pet: For Bang-Hee before she went to Japan to change her face via plastic surgery.
- Nice Girl: Even when she finds out that Bang-Hee stole her identity, Myung-Hyun tells Jong-Won that the time she spent with her did not change the fact that she was nice to her.