Enemy Behavior

 describes various actions or tactics enemies employ while spawned in the game. While based mostly on when enemies are alerted to the player's presence, this can include behavioral traits observed while the enemy is unaware of the player as well.

Basic Pathing
When enemies attempt to engage the player, they will attempt to avoid obstacles (including other enemies) in order to reach them. When hidden by various means such as by the use of Shade, Loki's Invisibility, or Ash's Smoke Screen, enemies will still know the exact location of the player, aiming their guns toward your general location and/or walking up to the player when they move out of range. When new enemies are spawned, or enemies that were previously unalerted are alerted, will go to the location of the player or another ally (such as a Decoy.

Abilities such as Hydroid's Undertow suffer from the inability of enemies to continue to fall into his pool, since enemies that have sunken into the pool at the edge are objects that other enemies can detect, thus will stand directly at the edge of the pool, unable to go in until the enemies at the edge are dead. This kind of pathing issues can be exploited in some ways, however, such as standing on some kinds of boxes or objects in small rooms with doors on either side, as enemies will stop at a certain point and wait until the player comes down, often grouping up in massive numbers in some cases, allowing AoE weapons to make quick work of them.

When Unalerted
When an enemy is unalerted, they will walk around, chatter, or stay stationary while looking around casually. While their paths can be noted and remembered, enemies do not execute the same pathing routine every time, and may switch it up on occasion. It can be noted that while enemies are unalerted, problems with pathing become apparent, such as groups of grineer attempting to go into opposing rooms but neither side will move out of the way to allow this, causing them to get stuck in doorways you may need to cross without alerting them, which becomes almost impossible. Enemies may also spawn in large groups, making stealth kills more tricky to execute without alerting the others.

In the case of Grineer enemies with helmets, their helmets will sometimes oddly move independently of the facial mesh underneath when unalerted, with the mask "looking" in a certain direction while the Grineer walks forward and keeps their head centered.

When Alerted
An enemy becomes alerted when the following conditions are met:
 * An enemy spots a Tenno, Kubrow, Sentinels or other allies.
 * Spotting Wild enemies will also have the same effect.
 * The alarm in the area has been triggered, making all currently spawned enemies aware of your location
 * They see a bullet or arrow being shot in their line of sight (such as an arrow or bullet shot by their feet)
 * You shoot the enemy but they do not die instantly with a single shot, alerting that enemy. If they see you or you are not cloaked when they are alerted (even if you are behind an obstacle) all enemies in that area will also become alerted.
 * There is a Fire Hazard currently active on the mission.
 * Note that this makes stealth kills impossible as enemies will always spawn alerted and slightly more aggressive into finding you.
 * There is a very minor exception, with that being Latchers spawned from seekers, which spawn unalerted regardless of the alert status in the area or the alert status of the seeker, but only immediately after being spawned.
 * They see an ally being stealth killed (they will become cautions, disallowing stealth kills, but will not alert others unless the player is seen as well).
 * Oddly enough, enemies often do not notice or care if there is a dead body, which means occassions can occur where you can stealth kill many enemies in a single area, even enemies right next to each other.
 * Note that touching them will make them cautious however.

When alerted, as stated above, enemies always know the exact area of where you are, regardless if you make noise or not, although making noise will encourage enemies to go specifically to that spot. Moving far enough away from enemies while stealthed will eventually cause them to slowly path toward your location. And when you are unstealthed by any reason or means, enemies will immediately know where you are and go to your location even if you are hidden out of sight, which shows one of the flaws in the AI.
 * An exception is if the player is hidden while the enemy is alerted in some instances, such as seeing a dead body, which will make them cautious, but not fully alerted, and they will not alert any other enemies.

To become unalerted from an alerted state, several conditions must be met:


 * The alarms in the area have been reset by hacking a console that appears white on the map
 * Several minutes have passed since alerting the enemies
 * Enemies who were crouching behind cover will still continue their animation as if still alerted, but if the conditions above are met, they will be considered unalerted and can be killed stealthily.

Combat Behavior

 * Most humanoid enemies besides melee-focused enemies like Butchers or Prod Crewmen, and enemies who are disarmed, will attempt to find cover in most mission types. Exceptions include Defense, Excavation, and Survival type missions, where enemies aggressively move toward players or defense objectives and rarely take cover.
 * Enemies behind cover may wait for an opportunity to throw a Plasma Grenade, indicated by the enemy peeking up or around their cover a few times before lobbing the grenade.
 * Enemies are more likely to lob grenades at the player if they are attempting to take cover or simply are not moving. Players who continue to move around discourage enemies to throw grenades as they attempt to track the player instead. This does not completely prevent them from throwing grenades however.
 * Grineer enemies often use military-like tactics against the player, especially while in groups. Lone grineer may backtrack a ways to where a group of grineer are, then move along with the group at a steady place towards the player, attempting to overwhelm them with firepower while melee units rush in faster.
 * This causes one of the most exploitable AI errors of all, as enemies will often become confused for a while, walking in random directions while holding their weapon to their side without engaging the player, offering easy kills. This may be due to above, where the enemy attempts to group up with other enemies but they are killed, causing the confused enemy to wander in the general direction they were killed at.
 * If Shield Lancers are in the area, Grineer are more likely to backtrack once they notice the player, even if they cannot take advantage of the shield due to other units already behind it.
 * The only enemy units in the Infested faction that do not rush the player are Swarm-Mutalist MOAs and Tar-Mutalist MOAs, which keep at a medium distance from the player while using their devastating ranged attacks, as they have no natural melee abilities. This makes the Infested faction largely melee-focused which makes tactics that exploit AI pathing is ineffective at best.
 * Various Grineer units will carry inflatable barriers called Blunts, shown by a small pack on their back. Occasionally, they will throw it down and enemies will treat the object like cover, or players can also use it as mildly effective cover as well. The Brunt has a limited amount of HP, in which it will pop and deflate, remaining crumpled on the ground for an unspecified amount of time.
 * Tall enemies have limited use of the cover, one reason on account of them never taking cover in the first place, and secondly it makes them easy to pick off with headshots, as their heads will be over the barrier.
 * It can be mildly effective for the player against enemy bullets, but has no effect against the attacks of Bombards and Napalms.

Enemies Behind Cover
Enemies that are currently taking advantage of some sort of cover act differently then normal units. Some units obtain the ability to burst fire their weapons, even Ballistas or Corrupted Crewmen. Enemies are also far more likely to throw grenades at the player while behind cover, besides when shielded by Shield Lancers.

Spawning

 * Spawning describes when an enemy is rendered and placed into the game environment. In warframe enemies always spawn in set spots in any given cell. Due to how Warframe renders game environments and how it connects different cells together, these spawn points can be learned by players and exploited, noted below.
 * Enemies will usually only spawn if the player or an ally is far enough away and some time has passed, as well as the limit of enemies on the screen has not been reached.
 * They can spawn next to the player however, if they stay in the same general area for too long, which includes most extraction areas; This prevents players from idling too long in one area.

Enemies Under Various Crowd Control
A general list of various things enemy units will do when under the effect of various crowd control effects, abilities, or status effects.
 * While blinded by Radial Blind, Prism, or Reckoning, enemies will move toward the sounds made by players most of the time, but may stay put on one spot and simply aim their guns in the direction they last heard the player.
 * Enemies who move around will usually do so slowly
 * Guardsmen will rush the player and melee in their general direction
 * While under the effects of Radiation procs, enemies will be vulnerable to friendly fire. They will also begin to attack other enemies when the player moves out of range.
 * Enemies under Mind Control will follow the player, and fire on enemies when they get into range. Occasionally, enemies will be stuck to tracking the player even while being shot at, jumping onto a ledge high up can fix the issue.