Stealth

Security

Security of a map level is controlled by a central Security AI. The Security Level and Security Tally are displayed in the upper right corner of the HUD when viewing a map level. The Security AI uses guards, drones, and security devices as its eyes and ears. When suspicious activity occurs, the Security AI will order units to investigate. The area security depends upon detecting intrusion and then responding. Any kind of detection, security report, and especially battle will increase the Security Tally, which escalates the Security Level. Each time the Security Level goes up, the Security AI applies new and more dangerous responses. For this reason, stealth is very important to avoid overwhelming reaction by level defenses.

Detection

Guards, drones, and security devices rely on a wide range of sensors to detect intruders.

Visual detection

Enemies

Guards and drones can spot your team visually. Each enemy has a vision cone; hover over an enemy to see the cone depicted in the HUD in translucent red with radial lines. The cone also displays in the HUD during the enemy's turn. The cone is typically 90 degrees wide and 18m long. The animation of a guard often shows them glancing around, stretching, and doing other idle things, but their attention is not actually moving. The region they can see is fixed unless the guard is moving or turning. The vision cone displayed in the HUD is the actual area they are looking at. The cone is depicted at knee height on the guard.

Vision can be blocked or obstructed by obstacles in the cone of vision. Solid objects such as walls and tall stacks of materials will block vision entirely. This is displayed in the HUD as sections of the vision cone missing. Shorter objects and non-solid objects such as shelving only partially obstruct vision. Obstructed vision is displayed in the HUD as hatched yellow sections of the vision cone. A merc in the solid red section of the vision cone will be seen. A merc in a hatched yellow section of the vision cone will be seen if they are standing or sprinting but will not be seen if they are crouched or sneaking. Use the HUD camera view controls to carefully check whether a movement path enters the obstructed or unobstructed vision of an enemy.

If a standing merc has an obstruction between them and a moving guard and the guard's vision cone comes across the merc, the merc will automatically toggle to crouch mode to get out of sight. If a merc in the obstructed section of a guard vision cone toggles from crouching to standing, the player will be warned once and the merc will toggle back t crouching. If the merc toggles to standing a second time, they will stand up and the guard will see the merc.

Vision between platform levels is poor. A guard usually will not see a merc that is sneaking on a level above or below the guard, unless whoever is on the higher platform is near the edge. The vision cone and obstructed sections displayed on the HUD do not account for differences in altitude and the edges of platforms.

If a merc passes through the edge of an enemy vision cone only briefly, the HUD may flash a small red cone flash directly in front of the enemy. The size of the flash indicates how strong the near-detection was. If the red cone flash does not reach 50%, the movement was not enough for detection threshold and the enemy does not become suspicious. The merc got lucky.

If the red cone flash reaches 50% but less than 100%, their Alert Status will rise to Suspicious and the merc's Detected Status will rise to Suspected. The pending Security Tally will go up by one or more points. The guard will immediately turn to look in that direction, regardless of whether they have action points remaining, without waiting for the end of the current character's turn. It is possible that in turning, the guard will get a better look and spot the merc. Otherwise, on their next turn, the guard may move toward the source to investigate. After they reach the location, they will spend a couple turns moving around the area looking for the source. If they don't find anything, the guard will move back to their post. If they were on patrol, they will head to the next waypoint in their patrol.

If guard with an Alert Status below Spotted sees a team member, the guard's Alert Status will jump to Spotted and the merc's Detected Status will jump to Spotted. The pending security tally will go up one or more points. The guard will then try to engage in combat.

Cameras

Cameras can also detect your team visually. Cameras have a vision cone which is marked in the HUD with a red outline filled with translucent red fading with distance. The vision cone is depicted at waist level. There are two types of cameras. The most common type, the short-range camera, typically has a vision cone 90 degrees wide and 10m long. The other is a long-range camera with a narrower vision cone and more than 20m long. Long-range cameras are frequently inactive until the Security AI decides to activate them during a security escalation.

Both types of cameras are typically oriented to the cardinal directions. Cameras can be mounted high on a wall or on top of tall poles. Cameras will often rotate once a turn. Some cameras rotate back and forth. Pole-mounted cameras in the middle of a room may rotate in a full circle; the most common direction for rotation is clockwise.

Cameras are blocked or obstructed by the same things as guard vision. Blocked and obstructed regions of the vision cone are not depicted in the HUD. The height of the camera lets them see over some obstacles. This can make it hard to tell whether a particular location or movement path will be detected by the camera. A warning will display if the camera might see you, but it may signal false positives.

A merc will automatically duck behind cover if a guard looks in their direction, but there is no automatic protection from cameras. A merc will not automatically toggle to crouch mode if a camera swings in their direction. If a moving camera sweeps past a merc, briefly putting the merc in the detection zone, the camera can spot the mercenary. The sectors between the cardinal directions of a long-range camera are not safe.

The area below the camera mount is a blind spot. This blind spot is not depicted in the HUD. A merc can safely pass through a camera vision cone if they keep close to the camera mount.

If a camera spots a merc, the pending Security Tally is raised by one or more points and the camera will send a notice to the Security AI at the end of the turn. The Detected Status of the merc may be increased. The Security AI will usually send a guard on the next turn to investigate; the guard's Alert Status will be raised to Alerted. Alerted guards will not return to their post or patrol.

Audio detection

Guards and drones can hear your team when they are moving. The base range at which an enemy can hear a merc sprinting is 10m. For reference, the tiles found on many floor surfaces are 2m square. Certain character traits and Talents can modify the base detection range. You can enter sneaking mode by toggling the C button. While you are sneaking, the audio detection range is cut in half, so a merc with no modifier for Move Detection Radius can be heard sneaking at a range of 5m. A merc with the Thief trait has a modifier of -2m Move Detection Radius; they can be heard sprinting from a distance of 8m or sneaking at a distance of 4m. Noise modifiers are additive, so multiple traits and talents can reduce Move Detection Radius even further. A total of -7 modifier would allow a merc to quietly get within blade range of an enemy.

Gunfire can be heard at much longer distances. Depending on the firearm, unmodified guns can be heard at ranges from 25m to 60m. Many weapons can take a silencer or suppressor as a barrel mod to reduce the Noise radius. Silencers usually reduce max optimal range. Suppressors add critical damage bonuses because they cut down muzzle flash. The Noise attribute of a weapon displays the detection radius accounting for any attached mods. Blades make no sound at all, making them an excellent, if extremely short range (typically 2m), option for stealth.

Grenades can usually be heard throughout a level. It is usually a bad idea to use a grenade if you want to remain in stealth, though it will probably attract a lot of guards away from their posts if that is the intent.

Noise travels through walls with no obstruction.

A guard who hears a noise will immediately turn toward the noise, regardless of whether they have action points remaining, without waiting for the end of the current character's turn. The guard's Alert Status will rise to Suspicious. If the noise was a merc moving, their Detected Status will rise to Suspected. The pending Security Tally will rise by one or more points. On their next turn, the guard will usually move toward the source to investigate. If there are obstructions such walls in the way, it can take a few turns for them to reach the location of the sound. If the location is unreachable, they will get as close as they can. After they reach the location, they will spend a couple turns moving around the area looking for the source. If they don't find anything, the guard will move back to their post. If they were on patrol, they will head to the next waypoint in their patrol.

Other detection

There are many other types of detectors that use various sensory modes to detect intrusion.

Pressure plates

Detects any unauthorized person stepping on the sensor zone. An active pressure plate is depicted in the HUD as a red mesh region across a pinch point. If the sensor is disabled, the mesh turns gray.

Laser fences

Detects any unauthorized person passing through the sensor wall. A laser fence is depicted in the HUD as a vertical array of horizontal red lines forming a detection zone between two towers. Most laser fences are initially harmless except for detection, but the Security AI can activate "lethal" mode under elevated security protocol. The laser fence will then cause damage (usually not lethal) to any unauthorized person crossing through, in addition to detection.

Motion detectors

Motion detectors detect any unauthorized person sprinting through the sensor area. Motion detectors will not detect anyone sneaking through the zone, but the zone is usually large. A motion detector zone is depicted in the HUD as a red circle around the detector. Motion detectors are blocked by solid objects in the same way as a camera. The HUD display does not mark the blocked regions of a motion detector.

Bio-Scan Field

A Bio-Scan Field detects life signatures within a large area. The HUD depicts this as a blue fuzzy glow in the air. The field will trigger an alert if too many bio-signatures are detected; the usual limit is 1 signature at a time. If more signatures are detected, the detector raises a pending Security Tally. If the extra signatures leave the field before the end of the Turn, the pending Security Tally is removed and the Security AI is not informed.

Mines

A mine is a kind of motion detector that will trigger an explosion if an unauthorized person enters the sensor zone. It will detect intruders both sprinting and sneaking. The mine does not directly add Security Tally, but the explosion is likely to be heard by many enemies.

All of these sensors (except mines) will increase pending Security Tally by one or more points when triggered. The Detected Status of the merc may be increased. When the Security AI is notified of a detection, it will usually send a guard to investigate; the guard's Alert Status will be raised to Suspicious.

Avoiding and mitigating detection

At the end of every turn, security reports from guards and drones are delivered to the Security AI. Pending Security Tally is also submitted to the Security AI at the end of the turn and becomes part of the permanent security tally. Security reports from security devices are immediate; they do not wait until the end of the Turn. Reports of gunshots are also immediate, but the associated Security Tally is pending. The Security Level may rise as a result of Security Tally. The Security AI can respond to reports and elevated security level in several ways, including sending guards to investigate, activating or reactivating additional security devices, authorizing lethal defenses on security devices, and summoning more guards and drones. Stealth is the art of avoiding detection or mitigating the effects of detection.

Avoidance

The most direct tactic in stealth is to avoid all sources of detection. It is easy to see the locations of security devices. Click H to highlight important features of a level, including enemies and security devices. A couple turns of observation will reveal the motion pattern of moving security devices, making it easy to avoid their sensor zones.

Guards and drones are harder to avoid. Some guards have stationary posts and may rotate in a predictable pattern. Others will move about the level on patrol routes. Certain Talents can predict the motion of a guard, increasing your ability to avoid them.

When the team enters a map level, they may not see all of the guards. The team will only detect guards within 60m of a teammate. Once a guard is detected, the team will continue to know where they are even if they move outside the 60m range. But unexpected guards can disrupt plans. If a merc makes a long movement toward a goal, they may discover unknown guards in the way and have to reevaluate their plan. Their ability to adjust their route may be limited if patrols or moving security devices have shifted behind them. Shorter movements will allow opportunities to adjust but may not be as efficient in use of Action Points.

Undiscovered guards do not start moving until they have been discovered. A moving guard will not suddenly appear on the HUD during the guard's turn. However, the Security AI may summon more units at the beginning of a turn as a security escalation protocol, or may send instructions which awaken an undiscovered guard. This will cause the new or awakened guard(s) to appear on the HUD at the beginning of the turn, and sometimes they will have initiative which lets them move first which can make it seem they walked into detection range of the team. Summoned guards and drones usually appear near obvious entrances--doors, elevators, ladders, drone chutes, etc., most of which your team cannot use. Be careful near such entrances.

Dead zones

Cameras have dead zones beneath the device. A merc can walk through the vision cone of a camera without being detected if they keep close to the device.

The sightlines of guards, drones, cameras are obstructed or blocked by objects. A merc can stand or run through a part of a vision cone which is blocked without being seen. A merc can crouch or creep through a part of a vision cone which is obstructed without being seen. Blocked and obstructed visual regions of an enemy is depicted by the HUD as missing or yellow hatched sections of the vision cone. Blocked and obstructed regions of security devices are not displayed by the HUD but can be estimated by careful examination of lines of sight.

Motion detectors are also blocked by objects. A merc can safely run through a region of a motion detector which is completely blocked. A merc can creep or crouch anywhere in a motion detector zone. Blocked regions of a motion detector are not depicted in the HUD.

Long-range cameras appear to have sectors between the cardinal directions where the device normally points which appear to be dead zones. Beware that rotating detectors may sweep across those apparent dead zones when it moves from one cardinal direction to another.

When in or moving through a blocked or obstructed detection zone, remember that the mercenary may still be detected by other senses, observers, or detectors. Watch for warning tags of potential detection when planning movement.

Sneaking

When laying out a move, the HUD will provide a yellow warning marker if the movement will enter the Move Detection Radius of an enemy. Audio detection is cut in half by sneaking. A merc can run to just outside the Move Detection Radius of an enemy, then toggle to sneaking to move a little further. This can allow the merc to pass near an enemy quietly or get closer for an ambush.

Sneaking will also allow a merc to move through an obstructed portion of the vision cone of an enemy or camera, or through the detection zone of a motion detector.

Suppressing sensory footprint

Certain Talents, Traits, and equipment can reduce or eliminate one or more forms of sensory detection. Both the Vanguard and Cybersword have talents to move silently or even invisibly for a short time. Vanguard also has a talent which can reduce the noise footprint of the entire team. Agent Ex has a talent to obscure movement noise within a region.

Interfering with security reports

A prepared team can interfere with reports to the Security AI in several ways.

Stunning or disrupting enemies

A stunned guard cannot send a report to the Security AI at the end of a Turn. Certain Talents and equipment can cause a guard to be temporarily stunned. This gives the team the chance to escape the area or to kill the guard before the report goes in. There are also Talents to disrupt a drone, either stunning it or spoofing its sensory units.

Security protocol talents

Certain talents such as K-Protocol talent can remove pending Security Tally.

Leverage

Some varieties of Leverage can block or delay security reports or remove pending Security Tally.

Distraction

Noises can be deliberately used to draw guards away from their posts. A merc can do this by sprinting within the Move Detection Radius if they can get away in time without being spotted. A safer method is the Vanguard Lure talent. A fully boosted Lure can distract an entire group of enemies. When the enemies immediately turn toward the source of the noise, mercs may be able to cross an area previously under observation. It will also keep the guards busy until they finish investigating. Beware that while guards are investigating, it is difficult to predict which way they will move or turn.

Killing

A team can kill isolated enemies. This serves several possible functions. A stealth kill can eliminate an enemy who is in your best path to a mission Objective. Killing guards will reduce the variables to track and reduce the risk of detection. A few early kills can improve your advantages for a later loud assault on a goal. If a merc is in imminent danger of being detected, a quick kill can keep the Security AI from learning of intrusion. Killing a guard will remove all pending security tally from that guard and prevent any security update which has not already been sent to the Security AI.

If a merc is Spotted but there are no enemies left who are Alerted or higher to their presence, the merc's Detected Status will drop to Hunted. A merc can never drop back to Hidden once they have been Hunted. But this means that if you can kill all the enemies who know about the intruders before more enemies are Alerted, the team can sink back into obscurity.

Killing can be done with a quick assault or by ambush. There are several methods for ambush. Team members can sneak close to an enemy or hide near their predicted path, then strike when close. A merc can deliberately make a distracting sound and draw an enemy into an ambush. A guard moving toward the source of a noise will use the shortest route. Note that most guards will not move through closed doors; this may affect the route they take. A merc can trigger a security device, accidentally or deliberately, then lay an ambush along the predicted path of the guard that the Security AI sends to investigate. Once the target is close enough, the team can perform a stealth kill.

Killing is not a long-term solution. The Security AI will typically notice a guard hasn't checked in after four (4) turns and send someone to investigate. This will also add one or more points to pending security tally. Killing also runs the risk that your strike does not take the enemy down before they send a report to the Security AI, or that another enemy will see or hear your attack. If an enemy discovers a dead guard, their Alert Status will rise to Alerted and pending security tally is raised by one or more points. Certain Talents, equipment, and Leverage can delay notification that someone is missing, or hide or destroy the body.

Disabling sensors

Several Talents and equipment can be used to temporarily disable security devices. Cyber Knight, Vanguard, and Hacker all have talents that shut a nearby security device down for one or more turns.

A Hacker can also shut down security devices from within the local Matrix.

Some varieties of Leverage can disable some or all security devices on the level.

Disabled security devices will be unable to detect anything or report to the Security AI until they are enabled again. Since devices send detection reports immediately, disabling a device cannot prevent the report of a detection the device has already made. Rotating or moving security devices will not move while they are disabled. When they are re-enabled, their next sensor scan will be the same area as before being disabled. After that, they will resume their normal motion pattern.

Speed

Speed is a sometimes-neglected tactic for stealth. Moving quickly can reduce the time it takes to reach Objectives, keeping the Security Level lower than if you creep everywhere. It also enables mercs to reach a wider range of cover and hiding places. Sprinting helps mercs keep ahead of patrols or quickly cross a patrol path before the enemy gets there. In general, it is a good idea to run when it won't be detected. At the same time, a team should avoid over-extending movement. Using the full Action Points for movement and ending a turn exposed to discovery is a lot riskier than moving a slightly shorter distance and ending behind cover. Sometimes the risk is worth it, sometimes it is not.

If a merc plans to creep close to an enemy, they can run up to the edge of the Move Detection Radius before toggling to sneak mode.

Splitting up is another way to boost the effective speed of your team. If the team has several Objectives, reaching more than one at a time is a way to reduce the duration of the mission, keeping Security Level low and making it safer. Balance this against the risk of one party falling into deep trouble without support from the other parties. Make sure that the split parties have the Talents and Traits that will keep each one safe.

If an enemy has heard a noise or a security device has been triggered, sprinting can get the merc out of the area before someone investigates. Sometimes it is worth it to permit an enemy to hear a merc sprinting or to trigger a security device if you can get away and reach a goal quicker. And sometimes it is time to throw away stealth and make a dash to the exit. It usually does not matter for victory conditions if the enemy discovers you. Getting out quickly with little or no damage is often better than trying to sneak through to the end and risk a deadly confrontation.

Several Talents can boost movement speed by adding Action Points, adding Movement Points, or improving Move Speed. The most powerful are talents that give a boost to the entire team, such as Tactical Surge.

Heavy armor will impose a movement penalty, reducing Move Speed. Characters and mission teams focusing on stealth may want to use lighter armor that does not inhibit movement.

Boosting stealth