You're going to need fully upgraded towers if you even want to prevent these Demonic Spiders from rushing your kingdom, especially on Heroic and Iron modes. Notably, several of them are found inthe elite mini-campaigns.
- Rocket Riders can be this in Heroic and Iron Challenges. They can fly like Gargoyles and Imps which makes them immune to blocking and artillery, except that they have more health than Gargoyles and almost as much as Imps. What puts them here is their temporary Nitro Boost when they take damage, allowing them to speed past your defences if your DPS isn't high enough.
- Pillagers from the Hushwood and Bandit Lair levels have an ungodly amount of magic resistance and have an Area of Effect attack that ignores armour. Not to mention their huge amounts of health.
- Forest Trolls also deserve a mention. Take one of the Ogres or Yetis. Now give it even more health, and absolutely insane amounts of regeneration. And then the penultimate wave of their stage throws about a dozen of them at you. The only effective way to defeat them is via One-Hit Kill abilities.
- The same level has Worg Riders. While on first look they have a meagre 400hp, they are actually closer to 800hp (About as much as an Ogre) because once the Worg Rider's hp reaches 0, the Orc Champions dismount themselves, whats worse is that they both have different armor types (Magical for Worg and Physical for the Orc Champion) meaning that you cannot rely on a single tower typenote and hope that they get wiped out before they run towards the exit. The kicker to all of this is that you will have to fight a lot of these guys, just after you managed to build your towers around getting rid of the Forest Trolls right at the same level.
- Troll Breakers. They're like Forest Trolls, sporting high HP, very high attack, and insane regeneration. Unlike Forest Trolls, they have less health (2800 vs 4000), but make up for that with 60% armor, which gives them far more effective HP than Forest Trolls against physical damage. Most non-magical attacks will take forever to kill them. Like Forest Trolls, the only effective way of removing them is via Instant Kills.
- Taken literally with the Sons of Sarelgaz. They have buttloads of physical armour AND magic resistance, making them Nigh Invulnerable.
- Demon Legions have good physical defense instead of high magical defense of other demons (which means you need magic towers to hurt them badly), have a good amount of health and explode when killed, but the real threat comes when they make an exact clone of themselves (with the same hp). If you don't give the initial Demon Legion prior damage before it duplicates, you'll be facing a dangerous army of them.
- Fallen Knights from the Curse of Castle Blackburn expansion. These guys have lots of health, high attack and zero physical defense but sport a stupidly high amount of magic defense. When killed, they resurrect as Spectral Knights, who can boost the (already high) power of the Fallen Knights and is completely immune to damage (even True Damage) from physical towers due to being a ghost, making even the Tesla x104 utterly useless. Long story short- they will screw you over should you concentrate one type of tower anywhere, and unlike Worg Riders who can be beaten through their resistance with enough Tesla, you have absolutely no choice and have to use magic and physical towers here.
- The Rotten Forest has its own variety of elite mook, the Swamp Thing. Like the elite mooks above, it has tons of health and constant regeneration; unlike the others, it has a ranged attack on top of that, meaning it can stand at a distance and bombard your soldiers to death before they even have a chance to engage it directly. While one might feel like having an Earth Elemental tank them, this is actually the worst possible idea — if an Earth Elemental dies during the level, it causes the poison pool to spawn another Swamp Thing that gives no bounty.
Kingdom Rush: Frontiers
- Sand Wraiths. They are an early game enemy counterpart to the first game's Necromancer. They spawn a horde of irritating Fallen ahead of them, heal nearby enemies, avert Squishy Wizard by having a high 800 HP, and hit troops rather hard with their ranged ability.
- Blood Tricksters. These guys have quite a bit of health, and will resurrect all slain savages around them into voodoo zombies with a lot of health. Worse still, your towers stupidly attack the zombies instead of aiming for the trickster first! If you don't use a Rain Of Fire or reinforcements to keep it busy, your defences will get overrun by stupid voodoo zombies.
- Saurian Brutes. They have a crapton of health (almost that of a Forest Troll), their laser whips hurt a lot, and they have a combo attack that ignores armor, hits an area and absolutely murders both heroes and troops quickly.
- Saurian Savants. These guys can summon Broodguards (gets faster when near death, easy), Darters (teleports, irritating), as well as Nightscales (cloaks when at half their health, very dangerous). If the Savant summons a Nightscale when it's halfway through, the Nightscale will probably cloak and waltz past half your defences.
- Speaking of said Saurian Nightscale, their invisibility protects them from up to half of the whole map which allows them to casually walk past all of your best towers. Countless Heroic and Iron attempts have been thwarted because they only make themselves visible at the very end of the map.
- The Rising Tides update is full of these things. They are elite stages after all:
- Blacksurge: Temporarily renders your towers useless and gets into a defensive stance where it regenerate much of its HP in seconds while also becoming immune to damage and being blocked.
- Bloodshell: Tons of health, physical attacks do next to nothing against it (Artillery does jack), and it can devastate your soldiers. Basically, a stronger Dark Slayer that forces you to use Mage Towers, which are useless against the...
- Bluegale: Immune to magic, casts storms that obscure vision, deal Damage Over Time to those caught in it AND makes you unable to select any towers affected.
- And of course, the Shadowmoon campaign adds some of these in too:
- Lycans, who will turn any troops he doesn't tear to shreds into other werewolves when the moon is full. Don't worry though, his incredible health regen and high attack means you won't have many werewolf soldiers to worry about. They're also in the first game in the Castle Blackburn expansion, with even more health this time, and since there's no moon mechanic there, they're compensated by having a much higher chance of turning soldiers into werewolves!
- The Vampiresa, especially if you've gotten too comfy with mass mage towers to kill the physical-immune ghosts. They've got sky-high magic resist and will instantly drain your footsoldiers for most of their health. Moving Lucrezia around and letting her use her Spin Attack to instantly kill them is essential to beat the stage.
Kingdom Rush: Origins
- Bandersnatches. They're Giant Mooks, but unlike most giant mooks which are Mighty Glaciers, these are Lightning Bruisers. They move extremely quickly by rolling, cannot be slowed, and deal a lot of damage to barracks especially with their area attack. If they manage to kill your barracks defenders, better hope you have more barracks behind or else they'll quickly roll their way to the exit.
- Arachnomancers. They will often summon most kinds of spiders (see Goddamned Bats) which are annoying to kill, and split into 3 spiders on death. Of course, your towers will tend to go for the spiders instead of the Arachnomancer himself.
- Blood Ogres. They're Giant Mooks resistant to magic damage, but the main kicker here is that they turn large groups of Gnolls into very fast and durable Blood Gnolls, which are thankfully weak to magic.
- If Worg Riders were bad, Mounted Avengers are worse. They're similar to the Worg Riders above- their beetle mount is fast and has good magic resistance, and when killed they drop their Twilight Avenger who has good physical resistance. Unlike Worg Riders, they appear in lesser numbers, but the Avenger and beetle have MUCH more health and are a lot harder to defeat.
- Dark Spitters. They have a good amount of health and armor, and they also possess a ranged dark spit attack that not only hurts a lot, it also deals a very painful Damage Over Time, and worst of all, turns soldiers/reinforcements/summoned units that die while infected into Shadowspawn to overrun your defences. Mercifully, while their info states that they regenerate health, they actually do not do so, and the other good news is that they can't infect or use their spit attack if engaged in close-combat, which they fare far worse in.
Kingdom Rush: Vengeance
- Valkyries are this game's counterpart to the Blood Tricksters from Frontiers, having a similar ability to raise dead allies into zombies. Unlike Blood Tricksters and their Savage Zombies which lack any resistances, Valkyries have massive amounts of armor while the Draugr zombies are more fragile but have a huge amount of magic resistance. Again, your towers that aren't Bone Flingers stupidly attack the zombies instead of aiming for the Valkyrie first. This makes it very irritating to take them down with slow-firing mage towers, which will target the Draugr instead, and if you don't use goonies to keep the Valkryie busy or Artillery/Goblirangs/Soul Impact to remove the horde, your defences will get overrun by stupid Norse zombies.
- Frost Giants. Like most Giant Mooks, they're slow but have a giant amount of health and deal giant amounts of damage. Unlike most giant mooks in the series, they also have high armor which forces you to either use Asra's Quiver of Sorrow to remove their armor or a Magic tower, and even with magic towers they still take a long time to die due to their health. The biggest danger by far, however, is that later waves throw them at you in groups of 3-4 at one go.
- Arcane Magi are somewhat annoying in the normal levels by having an armor-piercing area spell and the capability to teleport groups of allies forward. In City of Lozagon's Iron challenge where you only have one life, they become a legitimate threat as they will teleport massive groups of sheep forwards down the path. Your only towers in that level are the slow-firing but area-hitting Rocket Riders, the slow-firing and random-damage Orc Shaman which deals hardly anything to the mages due to their very high magic resistance, and the Orc Warriors Den which are unable to block or attack the sheep (Sheep in all games can't be blocked). Worst of all, your towers will most likely target the sheep that are further up the lane than the Arcane Magi, making it hard to damage them. Finally, despite being mages, they're also far from squishy. Your best bet is to tag them with Soul Impacts and hope it kills enough sheep to reset the cooldown time.
- High Sorcerers are similar to Frost Giants by being Giant Mooks with slow speed but giant HP and physical armor since you actually fight the Earth Elemental they ride. However, they're even less easy to stall since their attack deals heavy area damage and they can also instakill troops by turning them into sheep.
- Musketeers are a shorter-ranged version of Saurian Deathcoils, which ironically makes them more dangerous since they'll stick closer to the enemy front lines and not be targeted by your towers there. They have low HP but they quickly kill heroes and troops at a range with their guns and even have a very powerful, very long range sniper shot they will use every few seconds. Demon Goonies won't entirely null them since they tend to spawn in threes. Most importantly they can whittle down the health of Vez'nan's Archdemon (which you have to protect, and he doesn't heal HP) when three of them spawn on the final wave of the Final Boss fight.
- It's telling that the Subaquatic Menace expansion is a Brutal Bonus Level when the Anurian foot soldiers in the Anurian Chasers count as this, being Lightning Bruisers for Cannon Fodder standards. These Frog Men have decent HP, medium armour that reduces melee damage by 50%, appear in huge numbers, and if there are any troops not near the exit, they will perform a long-distance jump towards them that gives them a huge Dungeon Bypass while dealing considerable area damage in a Shockwave Stomp. This allows them to quickly overwhelm your troops while getting close to your exit to boot.
- By themselves, Anurian Infusers and Anurian Wardens are manageable. Together, they form a deadly alliance where the Anurian Infuser zaps the Anurian Warden with a ranged magic beam giving it high-HP Deflector Shields that protect the Wardens until the shields take enough damage. This magic beam has a short cooldown and the Infusers appear in decent numbers to give huge groups of Wardens shields. Unlike the Demon Lords in the first game that also moved forwards and attacked in melee, the Infusers are ranged units that stay at the back and shoot your troops while the Wardens tank and destroy your troops in front... and the Infusers will quickly reapply the Deflector Shields as soon as they disappear. The Infusers may have rather low HP, but that doesn't matter much when they're safe from your towers that attack the shielded Wardens in front.
- Snow Golems in the Frozen Nightmare mini-campaign are a threatening annoyance. They stay dormant on the map until certain waves and can be destroyed before they wake up, but this costs 200 gold (100 in Heroic) to do so. They're slow, but have a lot of HP, light armor, hit hard, can spawn near the exits and only give a measly 25 gold on kill. While they can't take out upgraded barracks with ease, they take a long time to fall and most importantly distract your towers from attacking other enemies, such as the Frozen Souls that will regenerate back to Frozen Hearts. Essentially they become a Sadistic Choice: use a hefty sum of gold, or face an irritatingly tough-to-kill enemy that can be spawned near the exit, draws fire away and drops chump change.