So this Kha'Zix guide should help lots of people when playing him. He's one of the best assassins in the game! He can be killed easy if your not careful. But he can jungle very easy. He has a heal a huge damage ability an inability ability a jump. what more could you want?
Look at the rest of the chapters to see more in-depth Kha'Zix Things!

For runes i like to take 5 lethality marks 3 damage marks and 1 crit mark. These can help you with assassination. for Seals i take all armor so i can live thru most fights. for glyphs i take 3 heath and 6 M.R so i can survive and stay in the jungle longer. For Quints i take all lethality again for assassination!

I take all the damage i can get in Ferocity but taking death fire touch to assassinate. in resolve i take mostly defensive and taking insight to reduce my sum spell C.D so i can use them more often. To kill and to escape more. To be annoying and all that. Its not easy to play Khazix tho so that's why i take these mastery's to help you.

I take hunters talisman 2to start with to get that mana regen it helps to start red than go to wolfs blue gromp krugs raptors with this start. I go with skrmishers sabre for true damage and killing power hydra is for killing and clearing waves of minions and jungle camps deaths dance if to take less damage and do more and help like crazy!but you can still be killed. I take swiftness boots to be fast!

i mostly max q first for that extra damage. I evolve e or q depending e for engaging or disengaging q for more killing power. i take r for my last evolved ablity so i can have that extra out of combat movement speed and invisibility. i dont really take w since i dont need it
to kill people with it evolved. you can if you want.

Summoner Spells i take are... Flash Because its good with kha giving him extra mobility and to juke people. Smite, if im jungling and to kill objectives dragon & baron. Ignite for champion killing. Exhaust to weaken the enemy and to make sure that cant kill you very fast. Take those summoner spells to help you.

Pros, High Damage kha is good because of the damage he can deal. very little can take his damage. Very mobile. He is very mobile cause when he kill an enemy with evolved e he can jump again and again and again and again so he can kill people and jump. flash is good with him so he can be very mobile champion.

Cons, Low defense. He does not have alot of defense. so he's squishy. but that doesnt mean kha cant kill anyone without dying. High Difficulty. He is SUPER hard to play. If hes not played right that in most cases means that you lose. so if your new to kha, just try to play a little safe.

Very Good jungler he can be very hard to kill if hes in the jungle and he can gank very well.
he can be hard if he is ahead in gold. in the jungle you can get lots of that.

mostly in team fights he will be a huge source of pain so if your playing kha wait until people are low than jump in and kill people that how most kha players get a pentakill.

Has great farming. With a hydra he can kill 50 minions at once when fed and can save and push tower because of this. thats why he's a good jungler cause he can clear very fast.