Blue:
- Strong against squishy champs like annie,twitch,soraka etc.
- Need at least 2 range enemy champs because you are getting blue form only from range champs like sivir, seraphine, Vayne etc.
- If enemy have 3 or more range or squishy champs pick blue.
Red:
- Strong against tank champs like aatrox, ornn, warwick .etc
- need at least 2 close combat enemy champs because you are getting Red form only from close combat champs
- if they have 3 or more tanks/brussiers pick red.
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Purple and speed are kinda troll picks but are good for normals, because purple and speed are for blue form you will still need at least 2 range champs.

On both forms it's same.
RED(leash)-> GOLEMS(smite)-> RAPTORS-> WOLFS-> BLUE(smite)-> GROMP-> SCUTTlE(herald)-> SCUTTLE(Drake)-> gank bot or mid
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With Q unlocked you are killing RED with bot assist, than you unlock E (go through walls)and go for GOLEMS (use smite) , after GOLEMS you go for RAPTORS, after RAPTORS you go for WOLFS, then kill BLUE (use smite), GROPM an SCUTTLES and at the and gank mid or bot.

You should have form to 13 minute or faster if not you will have big problems.Make sure you will get good form if not you will need to wait 4 minutes. (If it needed camp lane)

For ganks use your E ganks with Kayne are pretty easy you can gank lane from any wall but remember for tower diving make sure that minions are attacking tower or that you have R ready to use, than easy combo W from wall and R and if enemy have low hp it's almost guaranteed kill. Good form of ganking are coming on back of enemy than you have easy way to kill it's perfect for ganking bot, suppse such a sittuation: your bot are kept under the turretyou go from enemy side to attack from back it's really easy double kill with help of turret and bot laners. On blue good option to gank is to use your E and than attack enemy from wall with W than you have option to use R and than it's pretty easy. Even if you die in gank but you kiled enemy or you have assist it's worth, because you are one step closer to form.

Every combo was made on kayn level 11.
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Kayn have many combos but most comon is:
E->W->Q->R->aa->Q
Q->R->W->aa->Q
Q->W->aa->aa->Q
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Combs with Prowler's Claw
E->Claw->Q->R->W->Q
E->W->Q->Claw->R->Q
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Combs 1v2 (Shadow assasin/Blue)
E->W(on both enemy)->Q->R (go out from one to be closer to second)->Q
E->W(on both enemy)->Claw->R->Q
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Combs on RED (Goredrinker)
W->R->Gore->Q
Q->Gore->W->R->Q

Kayn is pretty hard on start but it's good to learn ganks and for learning how to secure draks, but it's hard to play in early game and for early duels.