Necromancers......

[Coleman]

How the hell do you kill them? On the level where they show up its game over, I may as well quit as they always get through and blow my 3 star run if not outright end the round with all their endless minions. I have tried mage towers, and archers. Archers and dwarven towers. Just archers.......it doesn't matter.

[Honorable_D]

Rain of Fire them for the quick and easy. Failing that, Tesla Towers absolutely decimate them and their minions. AoE Roots from the Ranger towers.

Basically, any reliable AoE will get rid of them with the Tesla Tower being the best.

[Coleman]

Ok so I need fully upgraded fireball, explosive towers and archers.....I will try that

[srsface]

They force you to build AOE, basically. Tesla towers are good if there's a solid choke point where they'll be forced to pass through, but I actually prefer getting a Big Bertha towers.

Rain of Fire is also super important. All you have to do is kill the warlocks that raise the dead, so dropping reinforcements on the first one to slow him down just enough til a second one is in range can help.

[Tjokka]

Pure Teslas works fine ;)

[greengoo]

i find that the ranger tower with the the vines modification helps me and thne i have my reinfrcment troops throw javlinins at them or havea ranged hero attack them. though tesler coils are pritty effective and so are muskatters with head shot. pritty much you needa two or three high level towers and ther jsut fire bal lthme if that not enough. dyslesic sorry abotu the spellling

[Brigadeer]

The best way to get rid of them is to split them from the minion wave.

He usually comes in at the back of a huge wave of people he's going to respawn.

Solution? Drop reinforcement on HIM at teh beginning of the wave so they get killed before he arrives.

Now if hes alone he should easily get focused fire by all your tower resulting in a death.

[VinnyMike]

If you're talking about the first level then your initial layout is probably bad. I only had two lighting towers on either side of the map. Just make sure you upgrade your mage towers as quickly as possible then upgrade your archers. By the time they show up your mages should be dealing with the necromances minions in one hit. Like others have said put reinforcements near them to seperate them from the group.

[Descri]

A way they have not mentioned yet on taking down necromancers is if you have a conjurer tower, you can move the stone golem right to the necromancer and the stone golem will kill it. The reason I mention it, is cause the stone golem has a small aoe (I think) and kills things fast, it also has a decent radius to work with. Though by far the most effective way to kill a necromancer is either of the two fully uprgaded cannon towers.

[Tom]

IF the necromancer is in melle, they will not summon minions, so using your reinforcements directly on them can buy you some time. Better yet, do it while they're under fire from a tower.

rain of fire also usually does a good job, tesla tower is great also with the statis field upgrade.

[Bingø]

Build a Tesla tower and max his AOE damage, it will kill all the skeleton summoned by the necromancer,then focus him down ;) .
You can also send your hero to fight them 1v1 .

[Searanox]

Maxed out Tesla towers, in pairs, will kill just about anything that's not a huge, HUGE monster. Foresake your barracks and build for aoe.

[Naked Burn]

Teslas for the win!! On the last level in Rift of Cinders, the one with Vez'nan, you can get by on Campaign mode and Heroic challenge building nothing but Teslas. Start from the left side of the bottom row and go right. They will annihilate the Necros, as well as everything else.

On challenges where you are barred form artillery, I find fully upgraded archers with the entangling roots fully upgrade to be the best AOE substitue.

[Makiki]

Rain of Fire and the reinforcements do it for me while the towers attack them.

[Dijad]

Tesla Towers are, sadly, pretty much the answer to every problem unless you are barred from using them. I say sadly, because the other towers arent bad at all, it's that the tesla towers are so GOOD. 1. They attack ground AND air. 2. those attacks can chain for massive effect focus damage when fully upgraded in map and world 3. AoE damage that is extremly deadly to all massed troops. This combination makes it the best all round tower, as it deals with two of the most insidious enemies in the game very well. Necromancers, its chains and AoE are going to hit him, thus ensuring his death and stopping his minion flow. Demon lords, even if he shields up and the tesla attacks a minion, the chain will eventually reach him, thus making his shielding rather pointless.

Thier only drawback is thier cost, and this is combated by using the archer buyback strategy. Simply fill in most of the map with cheap archers for the first few waves while acumulating money. With the 90% refund upgrade, it is then easy midgame to get a couple strategicly placed fully upgraded teslas after selling off enough archer towers. After that, its just more and more teslas towers, slowly filling in all spots with teslas. With this strategy I beat the entire last wave of the cursed forest not dropping a single reinforment or moving my hero.

[Master Knight DH]

I need to emphasize again that the problem is the lack of sufficient competition. Cannon explosions in Steam simply are too bugged to be useful, and Musketeers, Barbarians, and Arcane Wizards all have flow problems and don't even partial ignore the targeted DEF stat. Fixing both issues would showcase that Tesla has surprising reliance on Overcharge to not suck. Musketeers will be coming cheap for ranged armor busting, Barbarians will also be inexpensive reward for efficient micromanagement, Arcane Wizards will still have Death Ray and Teleport in addition to suddenly being able to hurt demons, and Big Bertha still has the equally awesome Cluster Bombs Xtreme (which ALSO got nerfed from in Flash) and can work with Dragonbreath Launcher. Oh, and guess what? All of these except Big Bertha cost less than Tesla.

But wait. What about the Necromancers? How *DO* you beat them without Tesla, or Rain of Fire star upgrades for good measure? Well, as pointed out, dump soldiers on him. He even runs on a timer that never stops and always resets upon reaching 0 or whatever number is involved, and he only summons skeletons if he is not meleeing when that happens. Make sure you have a healthy mixture of towers to deal with any minions too. He's meant to be a miniboss given that he even has 700 HPs going on, so treat him as such. In later waves, AOE is still handy, but also consider having Paladins with Holy Strike, Barbarians with More Axes, or Rangers with Poison Arrows. The former two will make their way to the Necromancer, and the Paladins especially will shake off the Necromancer's abuse. Poison Arrows will have the Rangers focus fire on the Necro, but make sure you have other guys who can stop the Skeletons or they'll become horror shows. Oh, and Cluster Bombs Xtreme also cleans up the Skeletons quite nicely, enough said.

Demons are really meant to be Glass Cannons who both check and encourage the Tesla x104, as analyzed here:
http://www.gamasutra.com/blogs/DavidHarlow/20131025/203042/Kingdom_Rush__the_wonderful_Campaign_level_design.php
But in case you want to know how to handle Demon Lords without relying on Tesla, basically, isolate them or if possible, kill them ASAP. Do not slow them down if you can help it, or they'll place shields on the second group of demons even sooner. If those are Hounds, however, slowing the Demon Lords down will actually be better if it means less shields on the Hounds. Also, the non-archer/Tesla advance towers can still use the following for dealing with Demons:
*Sorcerer Mage: Curse damage and Golem, Polymorph to a certain extent
*Arcane Wizard: Teleport, Death Ray to a certain extent
*Big Bertha: Dragonbreath Launcher, Cluster Bombs Xtreme for Demon floods
*Paladins: Shield of Valor and Healing Light
*Barbarians: Throwing Axes, More Axes with leveled micromanagement (to make sure of hitting only the healthy Demons)

Which brings up another thing: Demons' explosions only trigger when they die, so you can Rally your soldiers away from them just as they're about to die and they won't suffer the high damage that occurs, which will allow them to keep fighting the enemies right behind them.

Honestly, if anything is overpowered, it's the Sorcerer Mage and his excessive DPS for his mass-applying the Curse status, not to mention the 8 second respawn Golem that has mindless play involved.