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Basement Culvert (zs_culvert) (Groundwater in Counter-Strike Nexon: Zombies) is the second Zombie Scenario: Season 2 map in Counter-Strike Online. It is a survival-based map.

Official Description[]

Time after chasing the wounded Dione

Hello. This is Senior Researcher Soy from Aegis Institute. Unfortunately, we've missed a chance to capture Dione. However, it has been badly injured by us. I've received an order from the headquarters to continue the pursuit. We are requested to capture it alive but if that is impossible, we can kill him. Let's do our best, everyone!

LS team found Dione hidden inside the culvert after their continuous pursuit and have tired to capture him. However, Dione noticed it and went hiding into the darkness. At the same time, countless zombies are coming from everywhere to welcome the LS team.


While fighting zombies in the underground waterway that followed Dione, Dr.A learned that Dione was evolving on his own, but in the end, the capture failed.


Culvert takes place in a big sewage treatment plant.The players need to face the zombies coming from the sewers. In later rounds, Dione will start attacking players by rolling from the dark corners, spewing poisons from the ward above the sewers, and using its tentacles to make the game harder.

There are a total of 5 rounds with 3 minutes time limit for each round.


  1. This is Alpha team. We've found Dione. Dr. Soy, please answer me.
  2. Soy: It is Dione. It seem to be injure pretty badly. Capture him alive!
  3. Soy: Ah! Oops! We’ve lost him again.
  4. Soy: It still have the ability to move so fast even it was badly injured. Lets continue in our pursuit.
  5. Soy: What is that? Zombies!
  6. Soy: I think zombies are coming from somewhere connected with the Culvert!
  7. Soy: Give up the pursuit for now. We need to survive this raids first!
  8. Soy: Survive until the backup force from headquarters arrived!
  9. Soy: Look at the big waterway over there! That is Dione!
  10. Soy: Wait a minute. I’ll try to communicate with it.
  11. Soy: Dione is going to attack us. Be careful!
  12. Soy: Ah, what is this sound?
  13. Soy': Dione is right on top of us! It's collecting the poison! Run!
  14. Soy: Dione’s look different. I don’t have a good feeling about it. Please be careful!
  15. This is Alpha team. We can't hold anymore longer from the zombie attack. Where is the backup force?
  16. Soy: The backup force is reaching soon. Please hold on.
  17. Soy: How can this be.. Dione’s outlook has changed completely!
  18. Soy: It looks very dangerous. Be careful!
  19. Soy: Dione has disappeared into the waterway!
  20. Soy: Although with the hostile force, it is a blessing that Alpha team is still alive.
  21. Soy: Combine with the backup force and reform your battle formation. We need to pursue Dione.
  22. Soy: I think we will have an ideal soon if this culvert is connecting to another hideout.


  • Always run in the same direction to avoid being trapped by the zombies.
  • Lightweight weapons and splash damage weapons are suitable for killing and running from zombies.
  • Dione will only come rolling at certain directions.
  • Dione will start spitting poison.
  • Avoid being hit by Dione when he curl up and rolling on the area. You will die instantly if you get a direct hit.
  • Beware when Dione appear above the area as he will spew its poison. Jump at the right time to avoid being hit.


Honor mission[]

Title Description Task
A medal given to a person who survives till the end like a Phoenix
Gentleman! Do you think you have the tenacity to survive Zombie hoards and Dione inside a dark and narrow Culvert? Love a challenge? Prove to me that you can survive till the end under any type of situations. Note: Easy stage is not included. Survive the Culvert 100 times.

Release Date[]

Culvert was released on:

  • South Korea: 23 February 2012.
  • Taiwan/Hongkong: 6 March 2012.
  • China: 7 March 2012.
  • Japan: 14 March 2012.
  • Indonesia: 7 November 2012.
  • CSN:Z: 23 September 2014.


Radio tone

Dione's metamorphosis


  • Culvert is a sewer or drain crossing under a road or embankment.
  • Phoenix in classical mythology is a unique bird that lived for five or six centuries in the Arabian desert, after this time burning itself on a funeral pyre and rising from the ashes with renewed youth to live through another cycle. It is also referred as Ababil in classic Arab literature.
  • In this map, Dione had evolved into Siege Type Dione and later escaped to finally evolve into Angra in the next chapter.
  • During initial release, blood splatter will comes out if you attack the center of the map with certain melee weapons. This easter egg also can be performed in Trap, Another Truth (boss arena) and Last Ride (boss arena).
  • After Zombie Scenario Re:boot, you will meet 2 or 3 Siege Type Diones. Moreover sometimes when both of them are rolling one might get stuck in the dummy animation, but will disappear after some time.
  • There was a bug where the HP bar for the regular Dione may randomly appear and disappear. Despite Dione is being shot at, the HP bar does not deplete at all unless Bendita is used.
    • Using Bendita to attack Dione when it's attacking from the top floor will immediately end the round as soon as Dione leaves its attacking position. This is best used during the later half of the rounds, as demonstrated here (fixed in later update).
  • After the 26 March 2015 update, this is the only map in Zombie Scenario which keep its bonus round, and the only map in Zombie Scenario where the Pierrots makes appearance.
    • After the 20 October 2022 update of South Korea, there is no more Pierrots again who makes Bonus Round is disappeared.
  • After the 20 October 2022 update of South Korea, it was reduced from 15 to 5 rounds.