Stealth

Stealth is a mechanic which was first introduced in Update 7. When the Tenno is audibly or visually undetected by enemies, they are able to sneak past more easily to avoid combat, as well as perform devastating stealth attacks. However, suspicious activity raises enemies' alertness when encountered, and this increases the difficulty of the mission. When alert, enemies they may become more careful, get backup from other enemies or trigger the alarm control panels to summon backup from other rooms. A full alert occurs when the Tenno is directly detected by audibly or visual means: enemies will pursue the Tenno until they are too far out of range, but still remain alert and highly sensitive to the Tenno's presence for a period of time. Enemies noticing suspicious activity, but not the Tenno themselves will be on a minor alert, where they become more defensive. Alertness decreases over time.

While most missions in Warframe do not require or explicitly reward stealthy play styles, the game provides an assortment of weapons, mods and a different damage multiplier that enable an alternative game play for advanced players who seek challenges.

Alertness
Not to be confused with the mission type, Alert.

Failure to avoid direct enemy sight and hearing is one way of being detected, which puts enemies on full combat alert. When enemies detect the Tenno, they will attempt to pursue the Tenno, while getting backup by summoning nearby allies or activating alarm control panels. Additionally, their range of vision will expand and they will be able to spot you or your sentinel from far away, even if you disengage. You can tell once they clearly notice you or fire their own weapon that enemies nearby have become fully alerted. Even after you have been detected, backup in nearby rooms may not know what the threat is, and will be put into a state of minor alert.

Distant gunfire or suspicious activity (e.g. corpses) may temporarily put enemies in nearby map tiles in a minor alert. These enemies keep watch behind cover, or patrol with their guns raised and are more sensitive to your presence. As they don't know exactly where you are, they may not directly engage, instead being more careful, looking down corners and expanding their vision. This can usually be heard by the Tenno, as enemies talk while in this state. The map will change colour depending on the level of alert of the room. Cloaking will lower their alertness.


 * Enemies can only see things in a frontal cone, but their view can be further restricted by the environment. Enemies are bad at detecting objects at a distance, or anything somewhat above them. Toggle crouch for better stealth runs. You'll have a smaller model so you can hide your silhouette better. Also, it seems that enemies are less likely to notice you while you are crouching. The speed at which you move is more controlled, so you will be less likely to bump into the enemy before a stealth attack prompt appears. While more convenient for timing your attacks, rolling is a great way to shift longer distances while staying crouched.
 * For example, as enemy range-of-view (before alert) is <180 degrees, crouching in a corner nearby a door effectively exposes the back of any Grineer that walks into the room. As a different example, you hide behind a crate to block line of sight and conceal your presence. When an enemy is patrolling side to side (from your point of view), you
 * Loud noise caused by breaking objects, firing weapons, or activating abilities, will alert nearby enemies from all directions. The bigger the noise, the further it travels, and the more likely it will alert an enemy. However, certain weapons and abilities are silent, such as the Paris, Kunai, and Despair. These weapons may be used to perform ranged attacks while undetected.
 * Single hit kills are preferable, as a complete kill ensures your target cannot recuperate and alert attention. Performing an unsuccessful melee stealth attack will alert the enemy (this happens often when in a high level area, or when stealth attacking heavy Grineer), and so will bumping into enemies will cause an alert whether cloaked or not. Similarly, this includes failing to kill an enemy with a silent ranged attack or ability.
 * Control panels are scattered around the level and if activated by an enemy will alert the entire room, and may spread the alert to the whole level. Killing the enemy before a control panel is touched (they take about 1.5s to complete the alert) can still allow you to remain undetected. If an alarm was set off, you can reset the alarm by going to another control terminal and hacking it after clearing a room without further spread of notice. Do this quickly before reinforcements come and you can resume your stealth run.
 * Even when the control panel has been accessed and an alarm has been given, enemies will lose track of you when the last group of enemies you killed is not close enough to them to set them on alert. They will wander as if you were not detected and it is possible to finish a Stealth side mission this way.
 * By sprinting through and leaving the current room quickly, you can sometimes avoid the alarm being set off, or the alarm will go off, but since you are in another section of the level enemies won't notice. Using a frame with a sprint mod can increase this chance of escaping.
 * Cameras make loud alarms and alert nearby enemies when they see you, but again, if they are destroyed and nothing is in range to take advantage of their alert, you're safe. Rooms with two cameras are difficult to get past undetected without destroying them.

Stealth Attack
As long as an enemy is unaware of your presence, a stealth attack may be executed on them. To perform a stealth attack, approach an enemy from behind, and activate the stealth attack prompt.

Standard melee attacks are affected by a 400% stealth damage multiplier when attacking unalerted enemies, or when cloaked by an ability (Smoke Screen and Invisibility). This damage multiplier changes the color of regular damage pop-ups from white to yellow (similar to critical hits). Critical hits while under these effects will still appear yellow, but will multiply the 400% melee damage multiplier by the amount of critical damage on the weapon (e.g., 400% x 3x critical = 1200% damage). Successfully performing a stealth attack will deal a massive amount of damage during a special animation. The attack's final damage depends on the melee weapon type that's used:


 * 1200% total melee weapon damage for Daggers, Dual Daggers, Polearms, and Staves.
 * 2400% total melee weapon damage for Hammers.
 * 1600% total melee weapon damage for all other weapon types.

As these multipliers account for total weapon damage, equipped mods (including Critical Chance and Critical Damage mods) will also affect the stealth attack's final damage. Stealth attacks inflict Finishing damage which is unaffected by armor. Damage value pop-ups appear yellow.

Enemies are not always susceptible to increased melee damage for every melee attack. If the player comes into physical contact with an enemy while attacking it, the damage bonus will be temporarily removed. Attacking from different angles and giving the enemy some distance will help improve the consistency of the attack damage.

Enemy Eligibility
Mechanical enemies do not grant a stealth attack prompt. Mechanical enemies immune to stealth attacks are listed below.

Grineer Corpus
 * Roller
 * MOAs
 * Ospreys
 * Cameras
 * Turrets

Some Bosses, such as Captain Vor and Sgt. Nef Anyo, can be stealth attacked. The damage done will usually not be sufficient enough to kill them in one hit. Non-humanoid Bosses such as Phorid and Jackal are immune to stealth attacks.

Special Warden enemies grant bonus damage with stealth attacks, allowing a larger chance of instantly killing them, which is crucial in order to complete their host mission with the most points.

As a side note, sneaking up behind an unalerted MOA will grant increased damage but the Stealth Kill prompt will not be displayed. This will still kill the MOA in one hit (tested with level 20 Fusion, regular, and Shockwave MOAs).

Animation
Stealth attacks use the same animations as rear finishers. Like normal finishers, stealth attack animations vary according to what class of melee weapon the player is carrying. Examples of stealth attack animations along with other finisher moves can be found in the melee gallery page.

Affinity Bonus
Killing unaware enemies will trigger a Stealth Kill Affinity Bonus, which increases the amount of Affinity that a player gains from killing said enemy. The default multiplier value is 100%, however, this can be increased by performing a subsequent stealth attack within 30 seconds of the last one, which will add another 100% to the Bonus value, e.g. killing a second enemy stealthily will grant a 200% multiplier, the third granting 300%, and so forth until it caps out at 500%, whereupon any succeeding stealth kills will provide said bonus as long as they are made within the time limit. Stealth Kill Affinity Bonuses can be initiated using any attack as long as the enemy is unaware of the player's presence, though using Stealth Melee Attacks and silenced firearms can improve the chances of initiating an Affinity Bonus combo. The Stealth Kill Affinity Bonus resets if the next attack is made on an enemy that has been alerted.

A Stealth Kill Affinity Bonus notification appear in a player's UI to the left of the shield counter upon performing a Stealth Kill, which will display the bonus affinity value for that kill, as well as the time remaining for the combo.


 * Only enemy units will trigger Stealth Kill Affinity Bonuses. Environmental objects like Corpus Turrets, Security Cameras and Sensor Bars will not trigger or chain bonuses. Certain units like Sensor Regulators are also considered objects, and thus will not initiate Stealth bonuses.
 * Stealth Melee Attacks are recommended when attempting Stealth Kill Bonuses due to their large damage multipliers allowing them to kill enemies outright, and the fact that melee weapons are naturally silent. Ranged weapons that can deal massive amounts of damage in a single hit, like Sniper Rifles and Bows, are recommended when stealthily engaging enemies at range.
 * Warframe abilities like Shuriken can be used to initiate the Stealth Kill Bonuses. Note however that using Area-of-Effect Warframe powers like Radial Javelin may not initiate a bonus due to also hitting environmental objects as mentioned above, preventing the kills from being recognized as stealth kills for purposes of the Affinity Bonus.
 * Oddly enough, certain Warframe powers (like Paralysis) and Melee Combos that initiate stagger may initiate Stealth Kill Affinity Bonuses upon performing a Counterattack Finisher, even if the enemy was previously aware of the player.

Fighting Silently
Using noisy weapons and abilities will alert nearby enemies. Using max rank Hush and Suppress will render any weapons completely silent. Otherwise, the following weapons are silent to enemies:
 * Bows: Paris, Dread, Paris Prime, Cernos, Attica
 * Sniper rifle: Lanka
 * Explosive weapons: Ogris, Torid, Penta, bows with Thunderbolt
 * Throwing weapons: Despair, Kunai, Hikou (Prime), (Sancti) Castanas
 * All melee weapons, including thrown weapons
 * Sentinel weapons: Deconstructor, Stinger

The following Warframe abilities are silent to enemies:
 * Cloaking abilities (Smoke Screen, Invisibility)
 * Offensive abilities (Shuriken, Slash Dash, etc.) are silent only if cast under cloak
 * Ash's Teleport is silent only if cast under cloak, otherwise teleporting to an enemy will cause you to bump into it and alert it
 * Mag's abilities Pull and Shield Polarize
 * All of Vauban's abilities

Reduced Noise Level
Some actions however voices a reduced noise level, granting a plus for stealth gameplay. The following which produces less noise levels are:
 * Beam weapons (10.0m): (Synoid) Gammacor
 * Continuous weapons (25.0m): Amprex, Flux Rifle, Glaxion, Ignis, Quanta, Synapse
 * Dart weapons (10.0m): Bolto, (Telos) Akbolto

Tips

 * Be patient.
 * Check your surroundings to sneak up on an unsuspecting enemy without interruption.
 * Good timing means you can avoid patrols. Always position to attack enemies from behind.
 * Do not eliminate an enemy if it is being watched by another enemy. If enemies see a corpse that has not disappeared yet, they might be alerted for a short period of time. Be sure not to be in their line of sight.
 * Staggered enemies don't make sounds, but they become alert and will alert others if given a chance to recover. If you did not kill an enemy with a single hit, keep it staggered by stealthy means and you'll be fine. Cold procs will lengthen the amount of time an enemy stays staggered.
 * A fully upgraded Hush is able to make all primary weapons silent, and Banshee eliminates weapon noise with her Silence. Cloaking prevents visual detection.
 * Stand to the side of a door to open it and peer slightly by moving the camera. You can see around the left edge of obstacles by changing the camera to hang over your left shoulder (default is H).
 * If you have a Shade with Ghost ability, consider sprinting toward an enemy to activate it quickly.
 * Beware of breakable reinforced glass, unless it is part of the player's tactic to cause a controlled lock down to eliminate all enemies inside a chamber. This action will not cause a high alert.
 * The Corpus Turret is the only enemy weapon that is "silent" and won't generally attract attention if it attacks players.
 * Having a Sentinel equipped may be detrimental to your stealth ability, as it does not hide behind low cover. If you do bring a Sentinel make sure to remove their targeting precept mod or the weapon itself.
 * Throwing knives (Kunai, Hikou and Despair) are good weapons to quickly eliminate a small pack of enemies without alerting anyone
 * Very long range weapons such as the Latron, Snipetron and Vulkar, are less likely to attract attention. This is most likely because the weapon noise at the barrel is far greater than the noise impact.
 * If you can't finish off a target in one shot, attempt to eliminate them quickly with another silent weapon or they will be able to alert their allies.
 * It is advised to use a Codex Scanner while you are doing a stealth mission, due to the fact that the Codex Scanner can show you enemies within 50 in-game meters even through walls and behind cover.

Grievances
There are some flaws that have not been addressed.
 * The practicality of attempting assassination on heavy and shielded units, especially purely mechanical enemies such as Corpus MOAs and Ospreys.
 * If you aren't at the same altitude as the target, the prompt will not easily appear.
 * Bumping into an enemy will put them in an alert status and void your attempt at stealth killing them.
 * A Prompt will appear and disappear unexpectedly when the enemy are in alert.
 * Not all enemies can be stealth killed. It is hard to know whether an enemy type can be stealth killed until the player approaches behind the target.
 * After each stealth attack, you finish standing up, which might reveal your position. You will need to release and re-press the crouch button to return to crouch position. If you are using a toggle crouch key, simply press it during the animation to return to crouching when the attack completes.
 * Dropping off a ledge will also cause you to stand upon landing.
 * A glitch can occur when stealth attacking Infested Ancients, Heavy Gunners or Corpus Techs. Upon entering the stealth attack animation, the enemy will shrink to roughly the player's size. (This shrinking glitch can also occur when using Ash's Blade Storm. Blade Storm has a possibility to also shrink Grineer soldiers, as well as a few bosses, including Lieutenant Lech Kril.