Gas arrows take down AI quickly and quietly. They have an area of effect and can be used to knock out more than one opponent if the AI are close enough. The gas cloud lasts for several seconds, and new AI entering the cloud will also collapse.
Gas will also put out open flames.
Some opponents (like undead) are immune to knockout gas.
1.04: Gas will cause damage to the player if he enters the cloud.
Gas arrow: Expensive and illegal, these arrows release a poison gas that will immobilize opponents quickly and quietly.