Stealth

Stealth is a mechanic which was first introduced in Update 7.

How To Prompt an Assassination

As long as an enemy is unaware of your presence, a sneak attack may be performed on them. To perform a sneak attack, approach an enemy from beind, and activate the sneak attack prompt. Successfully performing a stealth attack will deal four times your melee weapon's charge damage. This damage is unaffected by armor or resistances. Some enemies, such as heavy Grineer, will not die from a single sneak attack, as they have a large amount of health.

Depending on what melee weapon you are using, your sneak finisher will vary. The finishing move varies by weapon-type. Daggers, Swords, Dual Swords, Heavy weapons, Staffs, Polearms, Boomerangs, Whips, Gauntlets and Dual Daggers all have unique finishing moves.

Enemy Eligibility for Stealth Attack

Bosses can indeed be stealth attacked

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

• Roller

Corpus

• 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 kill them in one hit. Non-humanoid Bosses such as Phorid and Jackal are immune to stealth attacks.

Detection

• Noise caused by breaking objects or firing loud weapons will alert nearby enemies. Non-silent Warframe abilities will also alert enemies. Certain weapons, however, are silent, such as the Paris, Kunai, and Despair. These weapons may be used to perform long-range sneak attacks. Certain weapons, when used at very long range, like the Latron, Snipetron and Vulkar, are less likely to attract attention.
• Loud weapons create "3D" noise. The bigger the noise, the further it travels, and the more likely it will alert an enemy. Banshee eliminates this noise with her Silence.
• The Corpus Turret is the only enemy weapon that is "silent" and won't generally attract attention if it attacks players.
• If not in cloak, bumping into enemies will cause an alert.
• Enemy range-of-view before alert is <180 degrees, so crouching still in a corner is a legitimate way to expose the back of a Grineer that just walked through a door. Enemies are bad at detecting objects at a distance, or anything somewhat above them. Hiding behind terrain will conceal your presence.
• When enemies are on alert, they will become highly sensitive to your presence. Their range of vision will widen and will be able to spot you or your sentinel even from far away unless you are cloaked.
• Performing an unsuccessful stealth kill will alert the victim (this happens often when in a high level area, or when sneak attacking heavy Grineer).
• In order to put the whole level in alert, an enemy needs to activate a control panel. Killing everyone before a control panel is touched can still allow you to remain undetected. However, gunfire will put enemies in other map tiles in alert temporarily. These enemies keep watch behind cover, or patrol with their guns raised and are more sensitive to your presence. They will "cool down" and can be stealth killed after a short period of time.
• 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.
• Cameras make loud alarms 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.
• By sprinting through the map 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.

Silenced Weapons

• Bows (Paris, Dread, Paris Prime, Cernos) are completely silent, able to multi-kill, and can pin corpses out of sight.
• Lanka.
• Bolto and Akbolto
• Explosive weapons (Ogris, Torid, Bows with Thunderbolt) are, oddly enough, silent.
• All melee weapons, including the Glaive and Kestrel.
• Throwing weapons: Despair, Kunai, Hikou.
• Cloaking based warframe abilities (Smoke Screen, Invisibility).
• Offensive based warframe abilities (Shuriken, Slash Dash etc.): silent only if cast under cloak.
• Mag's abilities Pull and Shield Polarize.
• Ash's Teleport: silent only if cast under cloak, otherwise teleporting to an enemy will cause you to bump into it and cause an alert.
• All of Vauban's abilities
• Stinger, the default weapon included with Djinn Sentinel, is silenced.
• Hush and Suppress, are rifles and pistols mods respectively that render any weapons completely silent at maximum rank.

Stealth Damage Multipliers

Melee attacks are affected by a stealth damage multiplier when attacking unalerted enemies, or when cloaked by an ability (Smoke Screen and Invisibility). These damage multipliers change the color of regular damage pop-ups from white to yellow, and critical damage pop-ups from yellow to red.

As of U11, it appears that regular, charge and finisher attacks have a 400% stealth damage multiplier. Assassination attacks will deal 400% of charge damage as "pure" damage (unaffected by armor, resistances, and weaknesses). Any added physical or elemental damage (ex. Impact damage from Heavy Trauma) is not factored in.

Tips

• Be patient.
• Crouch for better sneak runs. You'll have a smaller model so you can hide your silhouette better. The speed at which you move is also more convenient for timing your melee than running, and you will be less likely to bump into the enemy before the prompt appears. Also, it seems that enemies are less likely to notice you while you are crouching.
• If enemies see a corpse that has not disappeared yet, they will be alerted for a short period of time.
• If you have a Shade with Ghost ability, consider sprinting toward an enemy to activate it quickly.
• Rolling is a great way to move quickly while crouching.
• 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.
• Having a Sentinel equipped may be detrimental to your stealth ability, as it does not hide behind low cover.
• If the prompt does not appear, consider doing a charge attack.
• Kunai, Hikou and Despair are good weapons to quickly eliminate a small pack of enemies without alerting anyone.
• Stand next to a door to open it and peer slightly by moving the camera.
• Do not eliminate an enemy if it is being watched by another enemy.
• If using a bow or a slow fire rate weapon, be sure you are killing your targets in one shot to avoid alerting your target.
• You can see around the left edge of obstacles by changing the camera to hang over your left shoulder (default is H).

Notes

• Stealth kill will disrupt Shade's cloak. Warframe abilities will not.
• Loki's Invisibility will cloak your Sentinel.
• Against high level enemies, successful stealth kill are not guaranteed.
• Consecutive stealth attacks are possible. It would take the victim a split second to be alerted after being stealth attacked, but not immediately.
• Your Warframe is immune to toxic damage during the attack animation when stealth attacking a Toxic Ancient. You will resume taking health damage after the animation has ended.
• When stealth killing with any heavy melee weapons, the camera will cut into a cinematic view.
• The codex scanner can allow you to see enemies behind walls, at a fairly reasonable distance (about 50 meters.) However, if used to scan, it will remove the scanned enemy from your view.
• Using and holding down the trigger for Synapse before you cloak and when you cloak with Shade will still allow you to shoot while cloaked.

Current Grievances in The Mechanic

Since the concept of stealth is still a new one, there are some flaws that have not been addressed.

• The practicality of attempting assassination on heavy and shielded units.
• If you aren't at the same altitude as the target, the prompt will not appear easily. 
• 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.
• There appears to be no inherent benefits of stealth gameplay aside from the prompt for an assassination and lower enemy spawn rate, which is counterproductive given that weapons level via kill experience.
• 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 gltich 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.

Media

• Pangolin Sword (Swords)
• Orthos (Polearms)
• Kogake (Gauntlets)
• Dual Heat Swords (Dual Swords)
• Heat Dagger (Daggers)
• Glaive (Boomerangs)
• Fang (Dual Daggers)
• Hate (Heavies)
• Prova (Swords)
• Dakra Prime (Swords)
• Dakra Prime (Swords)
• Machete (Sword)

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