A knocked-out Security Guard.

Nika pinning a guard.

Humans including guards and agents can be knocked out, usually when they are attacked with non-lethal weapons. While knocked out, the unit is inactive; they cannot move, attack, or use items or most other abilities, and they have no vision or hearing. Knocked-out units also do not block or impede other units' movement; it is possible to walk over them with no penalty.

Guards, agents, or a rescued Courier or Prisoner become knocked out whenever KO damage is dealt to them. KO damage is dealt by non-lethal weapons, Flash Grenades and Flash Packs, the augment HoloCircuit Overloaders, and when guards breach doors. Agents can also become knocked out for 2 turns after using an Augment Grafter or Augment Drill to install an additional augment socket.

Being knocked out is a temporary status. Knocked-out units eventually wake up unless they are kept pinned; additionally, a knocked-out agent can be woken up using a Med Gel or a Stim.

Knocked-out units can be distinguished from lethally-wounded units by a triangular icon above them, a “zzz” animation, and the lack of blood. The triangular icon is green when the unit is pinned, otherwise it is red.

All drones are “KO immune”, meaning they cannot be knocked out. However, they can be rebooted for various reasons, which has similar effects to being knocked out.

While a unit is knocked out, this is indicated by a red or green triangular icon containing a number — the number is the unit's KO timer. The KO timer is initially equal to the amount of KO damage dealt to the unit, unless the unit is a guard with KO resistance.

At the start of each player turn, every knocked-out unit's KO timer is reduced by 1, unless the unit is pinned. When a unit's KO timer reaches 0, they wake up and become active again; when a guard wakes up after being knocked out, he also becomes alerted (or if he is a civilian, he panics instead).

A guard's KO timer can be increased using a Paralyzer, or by attacking him again with a weapon which deals KO damage. However, when a knocked-out guard is attacked, their KO timer is reset to the KO damage done by the new attack; it is not added to their existing timer. KO timers can also be reduced by the daemon Jolt.

Guards can have KO resistance, meaning they resist a certain amount of KO damage. Heavy Security guards always have KO resistance, and other guards have KO resistance while the daemon Watchdog is active.

When KO damage is dealt to a guard with KO resistance, their KO resistance value is subtracted from the KO damage to determine the guard's initial KO timer, down to a minimum of 1. If the guard's KO resistance is equal to or greater than the KO damage, the guard is still knocked out, and his KO timer will be 1.

Guards can have KO resistance, either innately or from the Watchdog daemon. If they do, they reduce all incoming KO damage by their amount of KO resistance, to a minimum of 1.

If an agent or guard stands on the same square as a KO victim, the KO victim is pinned. If a KO victim is pinned, they will not recover KO damage in any way for as long as they are pinned. An agent pinning a guard, or a guard pinning an agent has a special animation, but even if an agent stands on the same square as an agent or a guard on the same square as a guard, the victim is still pinned nonetheless.

An agent that is pinning cannot attack with melee weapons.

Note that if a KO victim is dragged by an agent, they are also pinned. While it is not possible to drop a dragged body on top of another downed body, it is possible to pin two bodies at the same time by dragging one onto another. It is also possible to have multiple KOed bodies on the same tile if something other than melee weapons are used to KO somebody while they are pinning somebody else, and in that case all the KOed bodies can be pinned by a single other person.

Guards will pin KOed agents that they see indefinitely until they are distracted by something else. If all of your agents on the mission are either being pinned or have been incapacitated, the mission will end, with all non-escaped agents counted as MIA.