Counter Strike Online Wiki

Electron or Trace: Rule A (zs_electron) is the extra chapter of Zombie Scenario: Season 7.


In a virtual training area, an enhanced virtual battle simulation of intrepid combatants takes place.


  • Collect battle data at a virtual training location.
  • Follow Evelyn's battle guide to the final target area.


  • Proceed through the game through the guide information displayed on the map.
  • If you press the [E] key in the place marked with E, the marked device will operate.
  • The red glowing structure can be destroyed by attacking and the game can proceed.

Release date

  • South Korea: 16 September 2021.
  • China: 29 September 2021.
  • Taiwan/Hong Kong/CSN:S: 6 October 2021.



M95tigernb.png Laserfist.pngLaserfistex.png HK X-90.png Scar oz-D.pngVoidpistol.pngDgaxe.pngBuffm2.pngDualswordnb.pngThanatos9.pngBearfury mk3.pngLightning fury.pngJetgunex.pngSgmissile.pngSgmissileex.pngMagicknife.png

Zbs addon stillalive.png Zbs addon explosionbullet.png


Wave 1
Evelyn msg.png
  • Hello. This is Evelynn.
  • Combatants. It's an honor to see you again.
  • I saw a ray of hope because of the good results in the previous stage.
  • I must have underestimated your fighting abilities.
  • You have demonstrated considerable combat power and countermeasures against large variants.
  • And we are one step ahead in securing data to respond to new threats.
  • We expect good results from this battle test as well.
  • Please do your best. I will always support you.
Wave 2
  • Evelynn: In combat, there are other threats besides the attack of the Infested.
  • Evelynn: Structures like obstacles are a major obstacle to the progress of the operation.
  • Evelynn: Destroy and enter.
Wave 3
  • Evelynn: Circumstances arise where you may need to pay attention to manipulating your personalizer.
  • Evelynn: Special care must be taken when handling firearms around suspected explosives.
Wave 4
  • Evelynn: Besides explosives, there are booby traps that cannot be destroyed by firearms.
  • Evelynn: Detour near the trap to gain access.
Wave 5
  • Evelynn: Activates or destroys surrounding features depending on specific circumstances to secure an escape route.
  • Evelynn: Common switchboards and objects like generators, etc.
  • Evelynn: Activate/destroy all targets marked with yellow targets, then move to the next area.
Wave 6
  • Evelynn: Depending on the characteristics of the battle terrain, the response method will vary depending on the difference between wide and narrow areas and elevation difference.
  • Evelynn: This battle is about moving after securing a target in a small space.
Wave 7
  • Evelynn: Manipulate/block the steam pipe and move to the next area.
Wave 8
  • Evelynn: Boomers and zombie dogs that explode after approaching in tight spaces pose a greater threat than normal.
  • Evelynn: Wouldn't it be better to get rid of them before approaching them?
Wave 9
  • Evelynn: Now, here's a situation to secure a ramp that integrates water discharge and water level control.
  • Evelynn: There are several ways to control the water level.
  • Evelynn: Destroy the structures and secure a high water level to swim or move.
  • Evelynn: Conversely, we find a way to move by activating switches such as valves on pipes.
Wave 10
  • Evelynn: A new type of mutant data that could not be obtained in the last large mutant battle has been obtained.
  • Evelynn: Please be careful as we plan to attack the fighters with a menacing explosive.
  • Evelynn: Defeating a large mutant unlocks the next section.
  • Evelynn: For reference, pay attention to the volume of the strong ventilation fan on the corner of the room.
Wave 11
  • Evelynn: Combatants. Again, you've lived up to my expectations.
  • Evelynn: Your fighting prowess will be an example to all your fighters in the future.
Wave 12
  • Evelynn: The tests aren't over yet.
  • Evelynn: Explosive obstacles and booby traps that appeared early in the deepening pattern.
Wave 13
  • Evelynn: Please move with more caution.
Wave 14
  • Evelynn: The following is a combination of tactical gear operation within the operational area and another combat pattern of large variants.
  • Evelynn: Sometimes tactical equipment, such as guns, is useful for opening access.
  • Evelynn: Destroy obstacles using the given number of shots as much as possible, then enter at the same time as suppressing the mutant.
Wave 15
  • Evelynn: You showed very good results, even in the operation and utilization of tactical equipment, even in a difficult battle situation.
  • Evelynn: We have high expectations for our combatants. You are the hope of mankind.
Wave 16
  • Evelynn: This time we have prepared a slightly higher difficulty situation.
  • Evelynn: This section tests your ability to escape in an emergency.
  • Evelynn: The goal is to use all your firepower to disable enemy equipment and then move on to the next section.
  • Evelynn: Concentrate as much as possible to secure a target and evacuate inside the blue hologram.
Wave 17
  • Evelynn: The recently reported large mutant, Agent B, showed a different fighting style from the previous large Infectants.
  • Evelynn: As it exhibits abnormal powers while maintaining human reason intact,
  • Evelynn: We have determined that Kronos' Super Soldier testing has come to a close.
  • Evelynn: To end all this before they become more powerful,
  • Evelynn: I beg you to join us in empowering us to fight Kronos.
Wave 18
  • Evelynn: Disabling the last gateway security system will end your primary combat power measurement.
  • Evelynn: We would like to express our deepest gratitude to the fighters who have fought valiantly so far.
  • Evelynn: It was more than Evelynn.
Final boss round
  • Evelynn: Good morning combatants.
  • Evelynn: I hope you get your equipment overhauled as soon as possible.
  • Evelynn: This test is about recently obtained data on Kronos' large-scale building weapons.
  • Evelynn: This weapon model is codenamed Colossus.
  • Evelynn: You don't have to be overwhelmed by the size of this weapon.
  • Evelynn: Because of its size, it also has weaknesses.
  • Evelynn: Attack the enemy weapons in turn, starting with the wings, this is only optional.
  • Evelynn: New counter-strategies are yours to create.
  • Evelynn: Guided missiles and drones that attack unspecified masses are destructive.
  • Evelynn: The laser pattern and the large fireball attack pattern have also been identified.
  • Evelynn: If you are being targeted by an enemy weapon, please leave immediately.
  • Evelynn: Then I wish you all the best of luck.




  • Electron means an extremely small piece of matter with a negative electrical charge.
  • In map 2 is taken from All-Out boss area.
    • There is some bug if you approach XT-300, you will die except if you use Titan Will's Add-ons.
  • This chapter depicts the third involvement of Evelyn after Episode Victor and Forest Keeper.
  • All bosses of this map from Zombie Scenario: Season 7 excluded Megalodon.