Slaanesh is Warhammer's thirsty, partying Dark Prince

Thirsty Slaanesh is the most complex and alluring of the Chaos gods. Like trapping your junk in an ironing board, but in a sexy way. Like being seduced by an attractive lawnmower. The Dark Prince of the Incognito Tab. 

Like all the Ruinous Powers, Slaanesh isn't necessarily evil. They represent art, creativity, romance, and beauty. But they're also the god of obsession and excess. So, under their guidance, what begins as romantic passion will always degenerate into something senseless and amoral. Every human desire is transformed and amplified. Every gratifying act taken to perverse extremes. They’re dedicated to the pursuit of earthly gratification and their ultimate goal is the downfall of all decent behaviour. Gluttony, lust, megalomania, hedonism: if you're doing too much of anything, Slaanesh is probably rubbing their hands and/or claws with sadistic glee. 

They’re the youngest of the Chaos gods, since they can only flourish in the minds of the intelligent, civilised races. A society must reach a certain level of development before Slaanesh's insidious presence can take hold. The barbarian tribes of the frozen north, for example, have little time for them—they’re too busy trying not to die to think about horny cave paintings. But as we venture further south in the Warhammer world, the Dark Prince's influence becomes stronger, particularly among the nobility. Wealth and birthright grant power, which can easily be leveraged by the Prince of Pleasure. If there was a Chaos god of gentrification, it'd probably be Slaanesh.

Their relationship with his Chaos brothers is complicated. As the youngest, they’re often seen as the weakest among them. Khorne is openly hostile to Slaanesh, whose decadence and sensuality literally send the Blood God into a volcanic rage. Likewise, the Dark Prince finds Khorne's artless slaughter tiresome, and takes a particular delight in irritating him. And, as you read this, someone, somewhere is probably shipping them. Slaanesh's part in the Great Game of Chaos is perhaps the most interesting. All the Ruinous Powers embody the type of excess that Slaanesh feeds upon: Khorne with his bloodlust, Nurgle with his plagues, and Tzeentch with his plotting. And, because of this, Slaanesh is feared. Somewhere, in the backs of their minds, they’re aware that their influence is always growing, and that one day their own obsessions might allow Slaanesh to eclipse them.

You might not think art, lust, and desire would have any place on a battlefield. And, as we’ve established, Khorne would probably agree. But Slaanesh's forces are lithe, quick and deadly. They beguile, confuse, misdirect. They’re a devastating hit-and-run force that gets bonuses for attacking enemies from the flanks or rear, and they have a selection of debuffing spells and abilities that prepare enemy units for the majestic killing blow. There’s grace, artistry, and poise to the butchery of Slaanesh, and their units embody this. 

The Keeper of Secrets is the Greater Daemon of Slaanesh, an imperious, striding titan of depravity who slices enemies apart with scything claws or befuddles them with foul magic. Alongside are the Daemonettes, Slaanesh's most numerous servants. They're mesmerising, graceful foot soldiers who dance into battle before shredding the flesh from enemy bones—ideally ones who are already locked in battle with another unit. 

As you might expect from an army that prides itself on speed and murderous effectiveness, Slaanesh can field some peerless fast cavalry. Seekers of Slaanesh are jarringly swift mounted warriors whose steeds come equipped with poison attacks. Seeker chariots grind enemies beneath their spiked wheels. And the Hellflayers are part-chariot, part-demented grounds maintenance tool: a blur of whirring blades designed to churn up bodies and feed Slaanesh's magnficent garden. That's right: it's essentially a horny, homicidal seed drill. And it's just as good at slicing up living people as it is dead ones. 

There are numerous reasons to pick Slaanesh as your Chaos god, and most of them have claws. Do it to seduce weak-willed enemy units and trick them into fighting for you, because you like the idea of every enemy dying while feeling confused and a bit horny, or just to make Khorne grumpy. Slaanesh can offer you all of these things and more. Why would you even consider resisting?