Chaos Knight

Try to get level 2 before your opponent and go for a kill with your support. Chaos knight has good kill potential with levels try to catch your enemy out.

Try to have chaos strike maxed by level 7 as it is your main tool for farming and will help with burst early.

Use Phantasm off cooldown not just to fight but also to farm faster unless you suspect a fight will happen soon.

Illusions scale with stat attributes, attack speed and movemet speed increases, health regeneration and some attack modifiers like lifesteal and crit.

Phantasm illusions are strong illusions so they can't be instantly killed with hex, dagon or drains.

Try to target and burst enemy supports and save heroes at the start of fights. Your illusions will generally be killed off as the fight continues.

With Blink Dagger you can use Phantasm, blink in and pull illusions on target by using Reality Rift.

Chaos Strike sustains Chaos Knight. Deal bursts of damage to him so he can't hit creeps easily and regain HP.

Chaos Knight's Phantasm applies a basic dispel on cast.

Either kills his illusions in the fights or disengage.

Items that deal AoE damage are good against Chaos Knight's illusions.

Crimson Guard and armor items are good at offsetting Chaos Knight's physical damage output.