Total War Warhammer/Tactics/Skaven

Why play Skaven

• Because you are a backstabbing bastard that cares little about the lives of your very numerous subjects
• You like bringing down classic high fantasy tropes with the power of raw industrial might, like Saruman
• DOOMWHEELS
• Even your most basic Skaven is by all standards batshit insane and CAs Voice Acting is spot on
• You are an opportunist that takes advantage of other factions being distracted and like making plots
• Skaven are entirely unique to Warhammer, in no other setting there is something quite like them
• IKIT CLAW HAS FUCKING NUKES

Pros

• Numbers: Even at the highest tiers, you will outnumber your enemy easily. Even higher tier infantry units outnumber every enemy unit and you have the units with the highest base model count in the game.
• Firepower: Your ranged units are easily unsurpassed by any other faction, this goes for your missle infantry as well as your artillery. Skaven have the strongest ranged roster in the entire game, and don't necessarily need a lot of micro to make the most out of them.
• Ambushes: Your normal movement stance on the campaign map lets you ambush enemy armies on the attack.
• Cost: Everything you have is extremely cost-efficient and your melee infantry in particular is dirt cheap.
• Under-Empire: You can establish hidden bases all over the world, siphoning other factions income into your pockets as well do some really crazy shit with this mechanic.

Cons

• DLC is mandatory: The big issue. The "The Prophet and the Warlock" DLC is absolutely mandatory to make your faction work on the battlefield; your roster will lack essential units like Ratling Guns and Warplock Jezzails without it.
• Mediocre Economy: Your economy is not the best. While many of your baseline troops are dirt cheap, your crazy weapons are not and your economy needs some time to get going, but even then, you will be overshadowed in terms of money by most other factions in your general vicinity. Special attention needs to go to your food economy, which is easily one of the biggest pitfalls an unexperienced Skaven player can fall into.
• Hard to play: You need at least a basic grip at how the game works to play Skaven, they punish mistakes heavily. Your troops may be numerous and dirt cheap, but have little staying power and will rout at the first glance of danger.
• Very hard start: Your starting positions (aside from Ikit Claw) put you in opposition of factions that have a lot of tools to counter your strengths. Start to fear Lizardmen, as both Queek and Skrolk have to deal with them very early on.

Universal traits

• Verminous Valor: The Leadership of Skaven Units depends on many Skaven are left, and will regenerate faster if the unit has more models left.
• Skitterleap: Skaven units get a speed bonus when they rout. Interesting ability, because it stops enemies from chasing your fodder.

Units

Infantry

• Skavenslaves: Cowardly, flimsy, expendable, cheap. Skavensklaves form the healthy base of any early game Skaven army. You send those guys in to die, not to do damage and to keep the enemy away from your weapons teams. Skavenslaves are by far the most efficient option to do just that. Can come with Spears if you want to give them more staying power against cavalry, but they are Skaven, do you really care if they die?
• Clanrats: Just a tier above Slaves, with the same attributes, albeit a bit more costly. Basic Clanrats without shields are not worth your time, you're better off just using Skavenslaves. Clanrats with shields will be your bread and butter for the early game, just don't get attached to any one unit of them.
• Stormvermin: As "elite" as melee Skaven can be. In contrary to Clanrats and Slaves, they actually have staying power (due to being armoured) and good leadership for a rat. Take them with Halberds but as with the other frontline options, don't expect them to move mountains. Your strenghts are elsewhere.
• Eshin Triads (DLC): A very odd unit that comes with some downsides but all the same weaknesses Stormvermin has. If you don't play as Snikitch, forget about them. Not worth your time.
• Death Runners: Whoo boy, those guys are really interesting. Probably the highest damage output a Skaven melee unit has, at the cost of a relatively low unit count and being overall very flimsy. That said, they can easily outclass even some elite units and are outright devastating against chaff. Their quick movement speed tends to push them towards a cavalry role, where they are best used.
• Plague Monks: They trade armour for raw damage, but unlike Death Runners, can actually take a beating due to a high model count. A good, albeit costly, alternative to Stormvermin in the mid- to late game for the more offensively minded player.
• Plague Monk Censer Bearers: Same weaknesses as Plague Monks, but come with Great Weapons. Great for stalling enemy elite units, but need to be kept save from enemy missles.
• Warp-Grinders (DLC): More of an utility unit than something you would straight up use in a fight. Their bonusses against large and AP damage have some merit, but don't rely on them to do any meaningful damage in prolonged combat. They can bring down walls und gates with ease, something to keep in mind during Sieges.

Missle Troops

• Skavenslave Slingers: Utterly useless. No, really. Not even their low costs can offset the glaring weakness that almost every unit can easily shrug off their missles.
• Night Runners: Your fast and manuverable skirmisher unit that also comes with Vanguard Deployment. Good at harassing the enemy backline and best used in that way. Come in Hybrid and Slingshot varieties.
• Warpfire Throwers: Where the fun begins. Ridiculously high damage output, solidly armoured. Need positioning to work right, but will absolutely demolish anything that you point them at, including your own units.
• Ratling Guns (DLC): You liked Fall of the Samurai? Then you are going to love these guys. They are machine guns in a late 16th century setting. Not terribly accurate, but with a high rate of fire, slowing enemies down, good range and a whopping 18 shots per volley. Did we mention that they have 36 models on large unit size settings? These should form your main gun line and are accessible pretty early on. Ikit Claws Workshop gives them tremendous bonusses, the first one making it essentially impossible for them to run out of ammo.
• Poisoned Wind Globadiers: Essentially grenadiers. They lob their toxic gas over your units heads and are pretty good at doing it. Preferred unit to bring against dwarves. Beware of friendly fire. Held back a bit by their short range.
• Gutter Runners: A straight upgrade from Night Runners, fulfill the same niche, but also come with poisoned shots.
• Death Globe Bombadiers: Straight upgrade from Poisoned Wind Globadiers, but even more deadly. They can rack up a ridiculous amount of kills very quickly but you need to be careful with friendly fire. Best used against large blobs of infantry, where they can wreck havoc against everything.
• Warplock Jezzails (DLC): SNIPER RATS. Long range, excellent accuracy, low rate of fire. Best used against single entity units or enemy lords and heroes, but easily have a place in most army builds.
• Poisoned Wind Mortars (DLC): Poisoned Wind Globadiers, but with range. They help a lot during tedious sieges, where Skaven don't get to make use of most of their arsenal. Their strenghts are somewhat offset by having a lower model count and being inaccurate.

Monsters& Chariots

• Rat Ogres: Strikingly similar to Greenskin and Chaos Trolls in a lot of respects; they move surprisingly quickly, pack a certain punch but can't take a beating and have awful leadership. They are useful for harassing archers and other units without armour and certainly have their place in the early game unit roster but become obsolete relatively quickly. Phase them out for Doomflayers as soon as you can.
• Doom-Flayers (DLC): Your go-to choice for cavalry until the late game. Surprisingly durable and, unlike many other chariots, can withstand prolonged combat. They pack a whole bunch of that sweet AP goodness and are the bane of almost any Dwarfen unit, barring slayers.
• DOOMWHEEL: The DOOMWHEEL is pure Skaven awesomeness. While being a little on the frail side, it moves quickly and can absolutely terrorize the enemy backline if it gets the chance. Warlock Masters and Ikit Claw can also use a DOOMWHEEL as mounts, keep that in mind.
• Hell Pit Abomination: Your big fat DISTRACTION CARNIFEX. It takes a whopping buttload of damage depsite having little to no armour and melee defence, but has decent regeneration and causes fear. One Abomination alone can easily tie up multiple enemy regiments in prolongs melee combat while your Ratling Guns and Globadiers do the actual work. And even if it dies, it explodes into more Skavenslaves that tie up the enemy. Have fun.

Artillery

• Plagueclaw Catapults: The more inaccurate, but more potentially damaging artillery piece. It lobs packs of toxic sludge over great distances. The one great strength that both Skaven artillery pieces have over enemy artillery is that their crews are surprisingly large, giving them a bit more staying power against direct charges by cavalry and melee infantry. Plagueclaws are best used against the more infantry centric factions, as their greater AoE capabilities help a lot with thinning out hordes and enemy archers.

• Warplightning Cannon: BAsically a great cannon with a lot more ZZAP and much less of a hassle to micromanage. It fires directly, but isn't bound to a high position to do meaningful damage and believe me, it will do damage. Three Regiments of these things will obliterate all but the biggest of monsters in short succession and still retain a lot of firepower against hordes, especially when the enemy is all clumped up in one space.