Counter Strike Online Wiki
Zombie scenario

Zombie Scenario is the second game mode introduced by NEXON Corporation for Counter-Strike Online based on a custom modification for Counter-Strike called as Zombie Riot.



Zombie Scenario pits up to 10 players against increasingly harder waves of AI-controlled Zombie. Money cap is doubled in this scenario and the amount obtained vary between type of zombie killed and the difficulty of the map. Extra health, damage and barrier durability can also be bought off the buy menu if the player have obtained a sufficient amount of money. The rounds will keep getting harder with different zombies pouring in while having more health and abilities.

If the player have Emergency Medicine, Battle Revival and Round Retry items, they can use for their advantage. However, players cannot use the battle revival when there is 30 seconds left in the round's timer. Any players who have just joined the game or died will spawn at the beginning of the next stage.

Compatible maps:

50% of the number of players must reach the targeted location by passing several obstacles and hordes of zombies. There are no time limit for this style. Any players who have just joined the game or died will spawn in 60 seconds. The team is counted as defeated if all the players died that round.

After 50% of the players reach the targeted destination, the player will be transported to boss battle arena. In this stage, the players must defeat the given boss.

Compatible maps:

The players must destroy the given enemies to advance to the next level. There are no time limits. Dead players will revive in 60 seconds.

Compatible maps:

  • Nightmare
  • Cube (this map has been removed after Zombie Scenario Re:boot)

Compatible maps[]

Icon Map Description
Lost city icon Lost City

Survival, 20 rounds (Easy & Hard), 50 (Normal).

50 rounds, all difficulty levels (After Re:boot).

20 rounds, all difficulty levels (After 4 December 2014 update).

5 rounds, all difficulty levels (After 26 March 2015 update).

Double gate icon Double Gate Survival, 20 rounds.

5 rounds, all difficulty levels (After 26 March 2015 update).

Trap gfx Trap Survival, 50 rounds.

30 rounds, all difficulty levels (After 4 December 2014 update).

5 rounds, all difficulty levels (After 26 March 2015 update).

Lastclue icon Last Clue Pursuit, 2 rounds. Last round battle with Phobos.
Chaos gfx Chaos Pursuit + Survival, depends on given map part. There are 4 ~ 7 rounds, depends on selected pathways. Last round battle with Siege Type Phobos.
Deadend gfx Dead End Pursuit, 2 rounds. Last round battle with Oberon.
NightmareSpecial Nightmare Nightmare Annihilation, 6 rounds. Round 1: Juggernaut, Round 2: Ganymede, Round 3: Prototype Phobos, Round 4: Siege Type Phobos, Round 5: Oberon, Round 6: Light Zombie Boss or Teddy Terror (Special Nightmare event only).


(Removed after Scenario Re:boot)

Competition annihilation, two player teams will compete to achieve the targeted score as the first.

Obtainable rewards[]

Best Rewards

Oberon's bomb Oberon's horn Phobos Tattoo


Regular Zombie
Comes in two different colored sub-types - green and orange. The green zombies throw Zombie Grenades, while the orange color has a faster attack rate, higher damage, faster movement and higher health.
Light Zombie
Has faster movement and slimmer body, making her hard to be hit. Weakest zombie.
Heavy Zombie
More durable and does higher damage than Regular Zombie but moves slower. Thick body makes it easier to be hit. Drops traps that will ensnare unaware players.
Voodoo Zombie
Zombies that heal their own teammates and has an average health level.
Psycho Zombie
A zombie with high health points and high attack damage. It can release black smoke to conceal fellow zombies.

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Zombie deimos
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The largest and toughest zombie, deals double damage to players with a large club and might leave traps as they run about. It has 35,000 HP or 450,000 HP (in extra-chapters) and on higher difficulties, they may run around instead of walking, allowing them to catch up with running players.
Replaces Juggernaut in later chapters. It has 4,000 HP (for host) or 8,000 HP (for origin) and can shoot a projectile that will force a player to drop their current weapon.
unlike the zombie modes, it is a direct improvement of the deimos, since it does not have a host version, and its hardening ability is replaced by the shock and charge skills, the latter is about charging players in their range, similar to phobos. It has 16,000 HP or 100,000 HP (in extra-chapters)

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Bosshp bg left bearboss
The first boss appears in Last Clue. It can emit a shockwave in its radius to force players to drop their weapon. It can also charge at players, possibly instakilling players similar to Ganymede.
Siege Type Phobos
The second boss appears in Chaos. Performs similarly to Phobos, but the addition of Voodoo zombie will makes things much more challenging, as it can heal Siege-Type Phobos if they are not taken care of immediately.
Boss in Dead End, and the last boss for Season 1. He can jump and disarm players from their weapon when he lands, or kill them if he lands right on top players regardless of their health. Oberon can also calls in a black hole to suck players closer to him, and then attack them at close range. At times, he will bend over and shoot bombs into the air, which will scatter around the map before exploding and dealing tons of damage.
Dealing enough damage to Oberon will force him to release his claws and double his melee damage.
Teddy Terror
The extra event boss, which only appears at Round 6 of Special Nightmare. It parodies some abilities from the previous bosses such as Oberon's black hole, Dione's tentacles or Revenant's fire storm.


Honor missions[]

Title Description Task
A medal given to players who have cleared Lost City for 400 times
[City Hunter]
Gentleman, do you remember the day when the zombies made a city to be a perfect death ruin? The city soldiers who were against the zombies till the end have been forgotten now but, you need to continue their honor. Note: Easy stage is not included. Clear Lost City for 400 times.
A medal given to players who have cleared [Zombie] Scenario Double Gate for 400 times
[Gate Keeper]
Gentleman, the scariest moment is when we feel that there is no way to escape from those zombies’ hands. The most brave soldier is the one who protects a death door against the fear of zombies which has tighten from the end edge of each narrow street. Easy stage is not included. Clear Double Gate for 400 times.
A medal given to player who has cleared Zombie Scenario Trap map for 400 times
Gentleman, assume that a vicious zombie group makes a trap for you. Will you still be able to run towards the front line even you know about it? Shout to them by surviving from limitless traps! I knew your entire hidden cards already! Note: Easy stage is not included. Clear Trap for 400 times.
A medal given to players who have killed Phobos for 400 times
[Phobos Slayer]
Gentleman, rumor has it that the monster has a blue color skin and some terrible things on its hands. I really want to meet the person who defeats such a monster for more than 400 times. Note: Easy stage is not included. Clear Last Clue or Chaos for 100 times.
A medal given to a player who killed Oberon for 100 times
[Oberon Slayer]
Gentleman, I’ve heard about the rumors of this monster. According to the rumor, The rear view of the monsters looked really horrible with its grey color skin and its cyclops eye. I will like to meet someone who have defeated that kind of monsters more than 100 times. Only available in Pursuit: Dead End map, easy stage is not included. Clear Dead End for 100 times.
A medal given to a player who clear all the maps in Zombie Scenario Season 1
Gentleman, we’ve sacrificed ourselves many times to fight with the zombies for a long time. Unlimited honor will be with you who did a great job in all of the battlefields. Note: Easy stage is not included. Clear Lost City, Double Gate, Trap, Last Clue, Chaos and Dead End 1 time.


  • Be generous. Always drop powerful weapons whenever you have a lot of money.
  • Always move with teammates.
  • Throw HE Grenades at a group of zombies chasing you to buy time for reloading or if you are blocked by a group of zombies.
  • Upgrade your attack power as much as you can to empower any weapons that you will use.


Loadingbg zs lostcity new

It has been a month since a research group was out of contact after being sent to the city that had been isolated due to Rex Virus infection. The government has dispatched Special Forces for investigation and they saw countless zombies in all over the city.

Just when they are about to report to headquarters, communication with the outside world were cut off and the zombies attacked them. The surviving humans from the attacks are now preparing for the final battle.

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Finally, the endless attacks from the zombies at the center of the city have stopped and the surviving soldiers have escaped from the place. They have tried to communicate with the outside world at a safer place and ends up reminding them that they were completely isolated.

They started searching around to figure out the reason of the isolation and while searching, they sensed someone's presence from the nearby deserted building and they found two people who are wearing protective clothing. When the soldiers called for them, they look embarrassed and ran away with their equipment. The Soldiers followed their back and entered a nearby building which is under construction but only found some destroyed equipment.

When they took the remaining equipment, they heard horrible shriek of the zombies. Realizing that the zombies were near to them, they built a protective wall by using materials from the construction site to prepare for the battle...

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Defending the construction site was not easy and our barriers have been destroyed at their hands and soon they will kill us slowly. A huge shriek and a blaring sound shook the earth just as we thought everything was over, causing the Zombies to stop their attack.

The sound echoed again, but we could grasp the words this time. A voice calling himself “Rex” told us an unfamiliar story. While we did not know who he was, we understood that he was the perpetrator of this case and capturing him would enable us to secure our freedom.

I gathered the survivors to the entrance of the rooftop- which was the source of the sound. There was to be no more delays. It's time to finish everything by entering the rooftop.

- From the advance unit commander Andrey's note found by the rescue team.

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2 days after receiving a distress call from the advance unit, we were deployed into the construction site. While searching the crossroads, we found advance unit commander Andrey and other advance unit members' corpses near the site.

Andrey was holding a note in his hand and he wrote about the horrible experiences he went through in this battle and also drew a map pointing to a particular area in the city. What was he trying to tell us about this location?

We increased our pace and head towards the spot indicated in the map.

- From rescue team signal corpsman 'Felix's diary'...

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A troop transporting the samples have left. The others entered the laboratory complex according to the last clue. All of the buildings in the laboratory complex are connected to each other towards the basement passage, and the size is much bigger as compared to with what they seen outside. An urgent retreat order from government has been delivered to troop Captain Ji Yoon Choi in border while we was about to start our investigation by entering the basement passage.

However, Captain Choi behavior changed suddenly when we reported to her about the current location of our troop. She ended the communication with the headquarters and requested us to conduct an internal investigation in the laboratory complex. If we continued on the investigation, it seems like we are ignoring the retreat order from the government, however, our will that led us to this place has already accepted her request.

What was she really trying to find out..?

- From rescue team signal corpsman 'Felix's diary'.

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Now, it can be bored by listening of what I'm going to talk about it. However, just few months ago, this place was like a living hell. The zombies' trap started from Lost City was really terrible till it annihilated one of the army troops... Even though so, our search party did a great job and we've found the last clue from the rescue team!

Actually, it was quite ridiculous to pursuit all the way to the laboratory’s basement from there. If we do not have an order from the government army captain at that time, we would be killed inside the chaos.

Yeah, everybody knows that this is the end of the story, and Dr. Rex is the main instigator cause all these incidents to happen. However, do you know that there is more than one siege type existed?

The secret is kept by the government and the real story start from now... Do you want to hear the truth that I've seen at that time from the blind road? Right after we've killed siege type Phobos, we've entered that unpleasant way by following on another two escaped Seize types....

- 1 year and 2 months after the Lost City accident, from the interview by an unidentified retired soldier with third-class media.


  • Map: Lost City.
  • Number of rounds is changed to 50 for all difficulty levels.
4 December 2014
  • Maps: Lost City and Trap.
  • Lost City: number of rounds is reduced to 20, all difficulty levels.
  • Trap: number of rounds is reduced to 30, all difficulty levels.
26 March 2015
  • Maps: Lost City, Double Gate and Trap.
  • Number of rounds is reduced to 5.
  • The completion required to get the respective medals are 400, instead of 100.
  • The freeze time is reduced.


Freeze time music

Survival music

Pursuit and Boss music

Pursuit and Boss music during Christmas event


  • The Zombie Scenario poster for Singapore/Malaysia quotes a few lines from Michael Jackson's song Thriller.