What's up, scoundrels?
I know exactly what you're thinking. "Man, I sure do love to play support, but my team doesn't know how to play around Winter Wyvern's ultimate and Riki is no longer the king of the 5th position. What noble steed should I ride on the lavender-scented road to Reddit-acceptable 9k?"
Don't stress your pretty little heads. I got you covered. Presenting: support Chaos Knight.
"But Saguine," I hear you shout. "Chaos Knight is a carry! He has a crit! He has illusions! He has a chocolatey voice which gives me chills in my nether regions and pitches me into sweaty states of arousal!" And you'd be correct, but in response: shut up and let me drive.
Similar to Abbi Jacobson and Ilana Glazer, supports fall into two broad cities. Defensive supports spend their days knitting doilies, watching The Big Bang Theory and generally existing in a state of bored, humourless limbo until someone looks squiff at their unnecessarily idolized carry, at which point they wet themselves and unload their spells like a squid deploying its ink sac. This is not about those supports.
The other side of the support coin wears leather jackets and stars in cigarette commercials. This side goes to work every day with dark glasses and a hangover, then gets in a fight with the water cooler before punching their boss. This side fits words like edifice into normal conversation and unloads money shots onto offlaners until they cry and resort to Iron Talon, the offlane creep camp and a large tub of Ben & Jerry's. This is Chaos Knight's category.
Let's talk.
Start the game. First pick Chaos Knight and select the safe lane. Prepare for moans from your allies. Intercept them with these exact words:
i am SUPPORTING
please choose an aggressive carry
Prepare for more moans. Make it clear that you're serious. Try avoid phrases like shut up, fuck off and I read this on Reddit. It'll only make things worse. Instead, say things I will get a ward and the courier or Will roam. If you have a mic, it's your honour-bound duty to say these in Chaos Knight's voice.
The enemy will pick to counter you. Gold-plated and America's second resort, this is your Trump card. They'll pick heroes like Lich, Earth Shaker and Lina. Use this moment to point out how they've countered a carry CK. Celebrate as your allies realize they can pick their own carry without fear of being countered. You're now in.
Spawn. Buy a ward, a courier, tangoes, a clarity and two mangos. Take a moment to scold whoever bought an Iron Talon. Place a deep ward in your safe lane and go contest the rune. Consider leveling Reality Rift first. Then, go into lane and start up the meat grinder.
You're fast. You're hella fast. From minute 0, start harassing the opponent. Threaten with Reality Rift animation cancelling. Fun fact: if you pay attention to the animation, you can tell where the hero will be pulled before you actually spend mana on the spell. Use this to try get off a long pull into the creep wave. Follow up with stuns and involvement from your carry. Get a kill and feed the muscle-mountain which rides on Armageddon. Get boots, get smokes. If the offlaner doesn't get the hint, keep killing him. Unless your carry is an idiot--which, as per Chaos Knight's theme, is a gamble--then you'll keep killing him. Otherwise, start, roaming. Mid laners never expect to get pulled into a swift case of Spanish-Inquisition-style death. Rush Arcane Boots and terrorize the map.
Standard build: 1-1-1, then max Reality Rift. At 11, you should be at 4-4-1-2. Get stats over crit: the armour reduction and proc chance is the same at all levels. Keep wards up, get smokes and dusts as need be.
First item: Aether Lens. Fuck Armlet. Fuck Drums of Endurance. Fuck Shadow Blade. What your Prince of Probability needs is a goddamn Aether Lens. 900 range Reality Rift? Sign me the fuck up. Right now, no-one can run away from you. With more pull than Akke at a single's bar, even a 2 second stun becomes lethal. Maybe you die, but that's because you're on the front lines like a proper soldier.
From the Lens, start expanding out. Vlads, Crest and Blademail are reliable followups; consider a late Silver Edge if you're against a Spectre or a Phantom Assassin. Come late game, drop your illusions and send them into towers while you keep a barrage of stuns coming. The threat of Reality Rift will keep enemies at a distance, because they have come to learn true fear. You can even start getting right-click items.
Tips and tricks
Reality Rift has a noisy, annoying, downright terrifying animation, all before you waste precious mana. Spam-cancel it in lanes to get inside your enemy's head. Teach them the meaning of probability paranoia. In general, use Chaos Knight's long animations to your advantage, because fuck knows it'll play against you at some point.
This same animation shows you exactly where the hero will be pulled. Open up a demo game and practice until you become better at cancelling bad pulls.
Chaos Knight has a deeply satisfying attack animation. Use it to deny creeps and keep the lane pulled back. Between ganks, don't be scared to shave some cream off the top and grab a last hit or two. If your carry pings you angrily, remind him that you're the fucking Percentage Paladin. Then go kill someone to make your point.
Mangos are really useful through the early game, before you get your Arcanes up.
Remember what I said about cigarette commercials? Well, Chaos Knight should be the one buying all the smokes. With Aether, a 900 pull range almost guarantees you'll get the jump on enemies. Kill their jungling heroes, salt their lands and raise their heads aloft as a sign of dominance.
Get a gem. Unlike doily-knitters such as Dazzle and Witch Doctor, Chaos Knight has literally a million HP and almost as much movement speed. Additionally, Phantasm allows you to keep true sight on the front lines, without risking the gem at all. The same goes for auras like Vladimir's.
At night, Chaos Knight only has 800 vision range. Be careful about casting Reality Rift on enemies on the fringe of your vision: having a sure kill scuppered by fog is as infuriating as being forced to do your taxes 2 seconds before orgasm.
Use Reality Rift to pop opposing/Roshan's Spell Block.
During a Roshan attempt, use your illusions to scout an area or tank Roshan (they only take 2x damage, unlike most other illusions). Decide between getting a Chaos Strike on Roshan or waiting outside the pit. Reality Rifting an enemy outside or--better--onto a cliff with you can really save your team if you get jumped inside the pit.
Because you're not relying on your Phantasms for right-click damage, cast it out of sight and use it to play mind-games. This is especially useful since the 50% chance of an extra Phantasm: enemies can't tell by simply counting how many muscular monsters are knocking on their door. If enemies initiate onto your illusion, they've just put themselves in a perfect place for a Reality Rift out of the base.
Phantasm gives you 0.5 seconds of invulnerability. If you're against heroes with powerful slows, or slow-moving projectile spells, consider saving it for a dispel.
Your illusions can trigger the armour reduction from Chaos Strike. Use them effectively.
What is the support Chaos Knight bad at?
As a melee hero, his stacking isn't super great. Leave this to the doily-knitters.
Against dual lanes his killing potential is greatly diminished. However, Chaos Knight in a trilane against a dual lane is an almost-guarateed bloodbath.
Mana draining heroes. Chaos Knight has difficulties with mana, and spells like EMP and Arcane Orb make him sad. Solution? Kill these salty, jealous fucks before they turn your mana into ma-no. Invoker and OD are especially susceptible at getting pulled out of position and slaughtered.
There you go. Ride forth, astride Armageddon, and make your enemies tremble. God speed.