Warframe has a huge variety of enemies to hack and blast your way through, so it stands to reason that quite a lot of them would be well set to ruin your day.
- Infested Ancient Disruptors and Toxic Ancients used to be this when their abilities had a 100% affect rate. ONE hit of the Disruptor used to screw up your interface, sap your shields to zero and, worst of all, drain your entire energy store. Since energy doesn't regenerate on its own unless you have the right aura mod (in which case it regenerates painfully slowly) one hit from a Disruptor when you're being attacked by a swarm of lesser infested would basically kill you in one go, especially since they knock you down. Toxic Ancients were surrounded by a poisonous cloud that bypasses shields and they left behind said cloud when they died. An inattentive player on anything other than Rhino (whose Iron Skin temporarily negates the poison and blocks the Ancients' knockdown attack) could die in seconds upon running into several of these noxious beasties, especially on higher levels when they spawn in packs and their poison damage was ridiculously up-scaled.
- Disruptors have been toned down with Update 14, only to be completely outclassed by Parasitic Eximus units released in Update 13. Disruptors needed to hit you, but a Parasitic Eximus just need to be within a certain range of you to rapidly degenerate your energy (and prevent regeneration), and the effect stacks with other Eximus auras and Toggled ability drains.
- Update 14 also made Toxics worse; while they don't have a passive aura of damage following them anymore, they do get a point-blank poison cloud they can cast at-will which can instantly kill you at most levels if you don't have strong enough health mods — which works wonderfully with their newfound ability to Pull foes into melee. They can also reduce the effectiveness of Gas damage on nearby lesser Infested, which was the one faction the element was actually useful on. A single Toxic Ancient can essentially take every rule about the Infested, and flip it on its head.
- Worst of all are the Ancient Healers (and their Corrupted equivalents). Rather than healing the enemies they accompany, they actually project an aura that grants 90% damage reduction and immunity to both status conditions and knockdown to every Infested (or Corrupted) accompanying them, turning even the squishiest Infested Runner into an infuriating bullet sponge. And just to add insult to injury, any damage you do to a buffed enemy will actually heal the Healer. Fortunately they don't gain the aura themselves (nor can they share it with other Infested Healers), but they turn Shoot the Medic First into an absolute neccessity, which is often rather difficult with a swarm of buffed-up lesser infested surrounding them, especially as they don't even have to be standing in your line of sight to project their aura and particularly as they're not very rare enemies, making you regularly have to deal with several at a time.
- The Fusion Moa is a bit more threatening than most Corpus units because of its highly damaging beam attack, but the real danger is that if not killed fast enough it can release a flying Drone with even heavier armor than its parent unit and the greatest firepower of all Corpus proxies, capable of stripping any Warframe naked in seconds at higher levels.
- Made worse in that, for some time after the release of Void Survival missions, the Drones were capable of spawning in after only 5 minutes while their parent Moas wouldn't appear for another ten (making the drones substantially stronger than intended).
- Grineer Napalms have a nasty AoE on their weapons - big enough that it can hit you through a non-Stretched Snow Globe - and the damage-over-time can mess you up very fast. To make matters worse they don't use a Painfully Slow Projectile like their Bombard comrades.
- As a rule of thumb, anything that's restricted to one map only will be one of these. Grineer Hellions who can fly and endlessly bombard you with missiles; or Corpus Anti-Moas, who fire energy blasts that cause large shockwaves on hit, which also knock you down when it directly hits... only to bounce and still be able to do harm. While they're avoidable, they have a tendency of aiming behind you, either from luck or on purpose making it very hard to see it coming.
- Drahk Masters are a Grineer unit which counts as a heavy, who summons packs of Drahk, which are armored Grineer-trained Kubrows. And to add to the demonic spideriness, they have a ranged attack which can knock your current weapon out of your hands, forcing you to go find it or switch to an alternate weapon; of course, you're not likely to notice that it's actually happened until a little while later, since the visual effect just looks like you've been staggered.
- The Mutalist Moas first seen in Update 15.5, which come in two variants. The Tar Mutalist Moas spew nasty gunk that creates a lethal puddle on the ground wherever it hits; to make matters worse, the puddle also slows any player unlucky enough to find themselves inside. The Swarm Mutalist Moas instead shoot out swarms of... something that latch onto players and objectives, damaging them and reducing their visibility. Both models come with the Shockwave Moa's stomp attack for even more fun. As it turns out, initially they were bugged so that their levels didn't scale with missions, leaving them stuck at high strength; while they're still dangerous, they're not quite as lethal as they once were.
- Update 16 brought the Grineer Manics, which combine Valkyr's tankiness and ability to become invincible with Teleport Spam, and throw Stalker's Dispel ability on top. You will learn to dread its deranged laughs.
- In Archwing missions, Hellion Dargyns. Their missiles deal a TON of damage, and give very little indication that they're hitting you, cutting down on your reaction time. And it's their only form of attack, leading them to spam as many missiles as possible. If that weren't bad enough, they also come in a Shield-Hellion version, which possesses an impenetrable, indestructible shield on its front; since they can turn on a dime, your best bet is to get into melee range, which is incredibly risky.
- Update 18 brings us the meanest spiders the game had seen up to that point - the Sentient combat units. Not only they are simply beefy and hit very hard, but over the course of your fight with them they adapt to your weapon damage type, gaining near immunity to all damage types and utility powers you used against them by that point. If you did not bring weapons with diverse damage types, you're screwed. If that wasn't bad enough, pray there's only one; because if there are multiple, they can share their resistances and split damage. Managed to get one down to nearly dead before it adapted your best gun? Its buddy will fly over, redirect all incoming damage to itself, and copy the resistances. Now you're back to worse than square one, with two nearly-unkillable drones with incredible damage output. Much like the Mutalist Moas, they were bugged at release, temporarily making them even worse than intended: they treated all three physical damage types as identical, so hitting them with Slash damage would also build up their tolerance to Puncture and Impact, and vice versa. About their only weakness is that they're relatively slow moving, but that in itself is undercut by their ludicrous 'disco ball' attack that can cross entire cells and slice your shields like they were made of cheese, and the absurd accuracy and AoE they have with their energy balls. Their resistances can be reset by using your Operator's powers against them, but good luck figuring that out on your own; the only hints the game gives you are in out-of-the-way background lore that's easy to miss, and even if you've read it, there's no reason to assume it would translate to gameplay like that.
- Recent updates leading up to the New War have altered Sentients. While they are now vulnerable to status effects, helping to reduce their durability, Sentient drones like the Battalyst and Conculyst no longer drop an orb of… something that fully heals your health and energy, making sustained combat against them much more dangerous in higher level areas like Veil Proxima anomalies or Lua on the Steel Path.
- Grineer Ballista are capable of one-hit-kills against players from across the map with no warning, and a glitch allows them to rapid-fire their one-hit-kill Vulkar sniper rifles when blind-firing around corners. Corpus Sniper Crewmen and Nullifiers are likewise capable of dealing stupid damage but lack the Grineer's hitscan weapon, are less common, and have a visible tracer to follow back to the source.
- Bursas were originally designed as slow tanks the Corpus would use as temporary blockades (hence their working name, Riot Moas). Their first appearance as the main enemies in the wildly-unpopular False Profit event made them horribly-buggy Lightning Bruisers that resisted most forms of crowd control and ignored pretty much all damage from the front. By the end of the event, most of the bugs had been fixed, but everything else had stayed the same. Unfortunately, when they returned to the game as permanent additions to the enemy roster in 18.4.10, it was clear that they hadn't been touched since the event ended, and they had come with a host of new bugs related to their spawning mechanics, making many high-level Corpus missions nearly unplayable.
- Update 18.5 fixed a longstanding bug preventing Shock Eximus auras from affecting players. Unfortunately, the effect they got was a proximity-based Magnetic proc: get too close, and you'll lose all your shields and energy. And if you were hoping to take them out with AoE powers before they got too close, think again: Nullifiers are one of the enemy types that can have the modifier. This was quickly changed with 18.5.6: the aura now inflicts an Electricity proc instead.
- On the other end, 18.5 also brought Hyekkas and their Masters. The Hyekka Masters are basically creepy old grandmas with tankiness somehow comparable to Bombards and who posses Scorchs' flamethrowers, as well as flame bombs which can create scorched terrain for a short period of time... and that's not all! They can also summon Hyekkas, Grineer-tamed Kavats, which are capable of hitting multiple times in one attack and thus dealing obscene amounts of burst damage. It's not uncommon to see Valkyr getting one-shotted by one of those things.
- The introduction of Sorties led to many veteran players discovering just how dangerous Sapping Ospreys could be. This model of the standard Corpus aerial drone deploys special mines, which generate pulses of AoE damage. The mines deal high damage, and the Ospreys love spamming them, so areas of a room can become totally carpeted with no safe room to stand. To make matters worse, the mines' fields appear to be a flat circle on whatever surface the mine attached to, but the actual hitbox is spherical, so it's not even safe to jump over them; the fields also penetrate walls and terrain, in case you thought you'd be safe behind cover. Fortunately, the mines can be destroyed, but prior to 18.1.4, they were invincible until they had actually started to emit the field.
- Executioner Nok's Carabus units in Rathuum were incredibly lethal at launch, dealing 15% of the target's max health with every tick of damage from their lasers. Unless you had some way to outright ignore the damage, you were going down, no matter how tanky you were. They were also small and hard to see, which was a bad combination in a game mode where staying still for too long is a recipe for death. To make things even worse, they were bugged to where they would attack continuously without the intended cooldown between attacks. Fortunately, the devs quickly issued a hotfix to add in the cooldown, reduce the damage to 1% of the target's max health, and increase the size of the unit.
- Similarly, Executioner Gorth had absolutely ridiculous amounts of armor at launch. At higher levels, he could simply sit there and laugh while all four players unloaded their infinity plus one guns into his face before hitting them with an unavoidable Cold proc and instantly killing them with his rocket launcher. The only way to deal with him was to bring a weapon with Corrosive damage to strip his armor. Post-patch, his armor is much less ridiculous and he's not that difficult to kill.
- Kuva Guardians. While they're much simpler to fight now, requiring Transference to fight them; either melee striking or Void Dashing through them to disarm them, they still edge into this territory as it all has to be done while dodging their one-hit Dash Attack before they are temporarily vulnerable to your own attacks. Still, they definitely qualified as this, requiring melee striking and dashing to make them temporarily vulnerable. Not only was this an unnatural chain of inputs, but it consumed a metric ton of the Operator's energy for each individual Guardian, all while attempting to avoid said Dash Attack.
- Saturn Six Fugitives. They hit hard, take many hits to bring down, and have to be captured like capture targets to earn additional Nightwave standing (and you're vulnerable during capturing), appears more often in missions than the Stalker, Grustag Three, and Zanuka Hunter, also each captured Fugitives only yield paltry 50-100 standing (as a reference you need 10,000 to level up). In addition, they have really nasty molotov cocktail attacks that are not only capable of taking down almost any 'frame in one or two hits, but can also bypass Limbo's Rift Walk ability for no discernible reason.
- Most of the Elite Terra units in Orb Vallis can be this, from the Terra Moas that possess a grappling hook attack similar to the Grineer Scorpion and the Terra Trenchers who can blindside unwary Tenno with their jetpacks and knock them down with ease, to the unseeming Terra Shield Ospreys which, if left alone, can and will eventually turn every enemy within range into mini Nullifiers with their shield aura. And if that's not bad enough, the high-level Raknoid units not only have multiple layers of armor and shields to punch through, but they're also immune to most if not all forms of crowd control. If a player isn't paying enough attention to Orb Vallis' Global Alert Level and destroying any Alert Beacons they see, they can expect an entire horde of these guys to show up and turn an otherwise low-level map into a Sortie-level warzone.
- The Cambion Drift on Deimos is home to a bunch of unique Infested units, and the vast majority of which are deadly in thick firefights. Thankfully, the Necramechs introduced on Deimos can hold their own against them, but to your frames and Operator, well, good luck. Oh, and they mostly are flat out immune to Viral procs.
- Carnis units initially seem like not much to sneeze at, and at lower levels they certainly live up to that reputation. However, they A: Have a decently strong projectile acid attack, B: Enough durability to be threats in melee range, and C: Can cling to walls and ceilings to ambush you, blending in surprisingly well. Their stronger (and thankfully rarer) Carnis Rex counterparts also possess a rolling attack to close the distance and can stagger frames with their melee attacks, making them death sentences in areas like caves and Isolation Vaults.
- Saxum units are also thankfully rare, but when they do pop up, dear god. Their main form of attack is a volley of Corrosive acid blobs fired from their shoulders which can and will shred you provided you don’t focus them down. Did we mention these things are very tanky unless you destroy their shoulders, and upon doing so they instead leave damaging trails all over the nearby area until they die? These things are the bane of many an Isolation Vault run for a reason.
- Jugulus enemies, unlike the latter two, are unfortunately rather common in the surface. You will quickly learn to dread these tanky Infested towers, as they can stagger you with piercing spikes from the ground, launch bone glaives that ignore projectile-based shields, and deal large amounts of melee damage. If the latter two ended Isolation Vault runs, this guy quickly tears higher level bounty runners to pieces.
- Deimos Therids share the Tar Mutalist Moa’s gunk throwing attack, but instead of it being a highly visible, not huge, and destructible gob of, well tar, the Therid’s cobweb is indestructible, covers a larger area, and tends to blend in with Deimos’ Infested ground. To make matters worse, they are very durable, and occasionally throw Infested units at you.
- Deimos Tendril Drones, unlike the other examples, are rather fragile, going down in one shot. Unfortunately, they tend to make up for that flaw by shooting powerful blasts that deal immense amounts of damage and being rather small, fast moving and flying targets that tend to be difficult to hit. To make matters worse, these things have a rather annoying attack preceded by a rather shrill screech that involves hurling itself at you, inflicting Interface Screw and deactivating any active abilities if it hits. While it does die instantly if you shake it off by rolling, the prior effects tend to be enough to render you vulnerable enough to get you torn to shreds by lesser Infested.
- The Angels of the Zariman update came with a rework focused on making the Eximus units more threatening, and it succeeded too well. They now universally possess a second health bar that renders them immune to crowd control abilities as well as making them Made of Iron. The auras got replaced with very powerful abilities fully capable of tearing even durable frames to shreds, to say nothing of Squishy Wizard frames.
- Blitz/Volatile Eximus have now gained an explosive shockwave attack that deals massive damage. Failing to get out of the way usually leads to a swift and painful knockdown.
- Energy Leech/Parasitic Eximus no longer have an invisible aura that drains energy slowly. Instead, they create bubbles that inflict heavy energy drain after a couple of seconds. Have fun going from full to empty thanks to not noticing said bubble. Although the fact that the bubble can be avoided rather then your energy drain being an irritating inevitability when the Eximus is lost in a crowd means this is the only Eximus that arguably got less annoying (or at least it would if it wasn't for the overall massive power boost that all Eximus received in the rework anyway). However, the energy drain is caused by forcing a magnetic status proc, which has the side effect of reducing your shields to zero. Hope you had full health!
- Leech/Sanguine Eximus were drastically buffed as well, now having a health drain bubble just like the Energy Drain Eximus that more effectively heals not just them, but their allies as well.
- Arson Eximus still have their Flame Blast attack, but it’s been buffed to always inflict a strong Heat status effect.
- Shock/Bioelectric Eximus now have three very strong electric orbs, dealing huge damage and Shock status.
- Guardian Eximus not only have the shield replenishing they used to, but now have three rotating shields that block all attacks, huge damage resistance to AOE attacks, and can project this protection to their allies. Thankfully, they do not protect from attacks from above.
- Toxic Eximus still have their Toxin aura, but it’s been buffed drastically. At higher levels, thanks to it ignoring shields, said aura may as well be an "Instant Death" Radius.
- Also introduced in Angels of the Zariman are Thrax soldiers, both Legatus and Centurions, Lightning Bruiser enemies with devastating attacks (Legatus units can become invincible for a lengthy animation and shoot three damaging beams that can Mana Burn, Centurions can deal powerful, staggering melee attacks and can Dash Attack you and inflict Mana Burn). They possess Overguard, just like Eximus units, too! And for even more fun, they have the distinction of having different forms of annoyance wherever you encounter them! At least they give out a healthy 5,000 focus upon killing them.
- Fighting them in the Zariman Ten-Zero will have them turn into a spectral form that needs to be killed with Operator mode not unlike Vomvalysts. They will return to physical form by consuming another enemy if you lose track of them, which isn’t all that unlikely considering the other foes present.
- On Lua in the Yuvarium and Circulus, they thankfully only spawn every five minutes. That’s because they drain life support at an even faster rate than normal the longer they’re alive. At least in the former they don’t pull the Reviving Enemy schtick.
- Good news: fighting Centurions in Duviri has them guaranteed to be solo, and they lack both their Reviving Enemy gimmick and Overguard. The bad news: they retain their powerful attacks that the Drifter cannot normally block, and the Drifter’s lack of Regenerating Shields, Static Health means they’re going down faster than a Warframe.
- The Circuit, especially in Steel Path, is extremely generous with spawning them, to the point fighting over five at a time is a common endurance. Combined with their speed, they will often put you on the back foot if you end up with less than optimal gear choices.
