Welcome to my Kennen guide, this guide will tell you the basics of Kennen, and if you're willing to take your time and read it, it will turn into an in-depth guide.

This guide is not finished, I got very tired writing and kepy making spelling mistakes, I will finish it in the morning (GMT time).

21st January 2012 - Added more detail to the 'Masteries' section (Why I spec each mastery).

22nd January 2012 - Added a 'Rotation' section, including rotations for team fights and 1 on 1's.

25th January 2012 - Changed the recommeded build - Changed Lich Bane for Abyssal Scepter, Reason: I think the Abyssal Scepter is more use***l for Kennen because I think the passive from Abyssal Scepter is more useful than Lich Bane's, also Abyssal Scepter gives mroe Magic Resist.

Pros

Extremely Fun
Nice damage
Amazing CC (Some of the best in the game)
OP ganks with ulti
Good farming ability with E and W

Cons

Squishy mid/late game without armour and MR items.

Greater Mark of Magic Penetration - These runes are good when fighting anyone really, it gives you the extra damage against tanks, and if used with Void Staff you can barely notice any MR at all.

Greater Seal of Armor - As Kennen is kind of squishy these runes help him in lane when fighting AD champs, it also helps in team fights when you are being focused or there is a lot of AD AoE.

Greater Seal of Vitality - I use these runes because many times I have been in the situation where I loose a fight but the enemy only has around 50hp left (Before I used these runes), and with the extra HP these runes gives you it can change the outcome.

Greater Glyph of Magic Resist - As the build doesn't have much MR I thought it would be smart to use some runes, and it payed off.

Greater Quintessence of Ability Power - These runes are greatly helpful, they make you very strong early game, whilst giving you an extra push late game aswell.

The reason I build AP offensive is self explanatory, as Kennen doesn't use mana therefore Utility tree seems a waste, and Kennens CD's aren't very long so CDR isn't that much needed.

Mental Force - This mostly helps Kennens damage a little early game, not really noticable later on though.

Sorcery - As I said Kennen doesn't really need CDR much, but a little is nice, as Sorcery is much more helpful for an AP champion than Alacrity .

Arcane Knowledge - I find this mastery very noticeable when fighting tanks, and if used with Void Staff and Mark of Magic Penetration it makes it seem like your enemy has no MR at all!

Havoc - I cannot think of a reason why you wouldn't use this mastery, you can't go wrong with an extra 1.5% damage.

Blast - I like this mastery, because it helps a little, but it also scales into late game making it helpful all throughtout.

Archmage - This is very helpful, and is used with Rabadon's Deathcap thats an extra 35% Ability Power!

Executioner - This is very helpful for finishing off enemies that are low on HP.

Summoner's Insight - This is useful for the reduced Flash cooldown, I have been in so many situtations where Flash just finishes cooldown and I get away from a potential death while using this.

Good Hands - I use this because the only other option is a mana regen mastery, and Kennen doesn't use mana, I also find this helpful for then you're protecting your Inhibitor Turrets and Nexus Turrts.

Swiftness - I think this mastery is very helpful, it can help you secure kills from slowly catching up to the enemy, hitting them with your Q and getting a stun on them, then finishing them off.

Runic Affinity - For Kennen this is mostly useful for Baron buff, as other players on your team will need red and blue buff more than you do.

Recommended

Sorcerer's Shoes
Will of the Ancients
Rylai's Crystal Scepter
Rabadon's Deathcap
Zhonya's Hourglass
Abyssal Mask

Tanky

Mercury's Treads
Rylai's Crystal Scepter
Lich Bane
Haunting Guise
Zhonya's Hourglass
Abyssal Mask

Core Items - Finished Build

Sorcerer's Shoes
Rylai's Crystal Scepter
Rabadon's Deathcap

Optional Items - To finish core build

Lich Bane
Will of the Ancients
Zhonya's Hourglass
Abyssal Mask
Morello's Evil Tome
Void Staff
Haunting Guise

My skill sequence is Q-W-E-Q-Q-R-Q-W-Q-W-R-W-W-E-E-R-E-E

I max my Q ability first ( Thundering Shuriken) because it is very good for harrassing and poking, it is your main damage spell, excluding your ultimate.
TIP: Use this spell in lane to harrass, and to initiate in fights, or for last hitting your enemy if they're trying to run away on low HP.

I max my W ability second ( Electrical Surge) because it does a nice amount of damage and it is a very good follow up spell from your Thundering Shuriken.
TIP: Use this spell after you have hit an enemy with your passive ( Mark of the Storm) of after you have hit an enemy with your Thundering Shuriken.

I max my E ability last ( Lightning Rush) because while laning it is better to be away from your enemy then close, and because early/mid game it is only really useful for getting away from ganks.
TIP: Use this to farm minions by using it to go through all the minions you can, then finishing them with your W ability.

I learn a point in my R ability ( Slicing Maelstrom) everytime I can, this spell is amazing for teamfights because of the amount of CC is does, it can turn around fights, I also use this in 1v1 fights to stun my target which makes them unable to hit me.
TIP: Use your R spell after you have hit your enemy with both your Q ability and your W ability, this means that the enemy will be stunned faster, giving them a smaller chance to run away.

This is my rotation for MOST fights, as I believe it has the best CC and burst.

1 on 1: I start with a Q Thundering Shuriken, followed by my W Electrical Surge, your enemy will now have 2 Marks on them, after this I go into them with my E Lightning Rush, they will now be stunned, while they are stunned you shuold use your R Slicing Maelstrom, by now your enemy should be at around 20% health, and your Q ability shuold almost be ready, when it is use it, and if needed use your Ignite on them to finish. If this doesn't finish them try to kite them until your W ability is off cooldown and use Auto-Attacks.
TIP: If you have Lich Bane you should stun them, and then get an auto-attack in for a lot of extra damage.

Team Fights: Before team fights you should constantly try to harrass the other team with your Q, as soon as the team fight starts you should run in with your E or R ability, getting a Mark on all your enemies, following by your R or E ability, depending which one you have already used, then your W, the whole of the enemy team will now most likely be stunned, after you have used your ulti you should start targetting enemies, using the rotation I have said above (1 on 1 rotation).

For Kennen I ONLY use Flash Ignite my reason is because Flash is a great spell for starting ganks or for getting away from a fight which you are going to die in, and Ignite is very useful in the laning phase when you don't want to tower dive but your enemy is on very low HP.

Early Game - At the start of the game I get a Doran's Shield, this makes your lane sustainability very good, meaning that you don't often need to go back to base, which also means more minion kills. Once I get 1550 gold I usually go back to base unless I NEED to stay in lane, when I do get back to base I pick up Boots and Hextech Revolver. After this you should be around level 6, when you get to level 6 keep on harrassing your enemy until they get to around 50% HP, then initiate for a kill, after that push to their tower, recall and buy your Sorcerer's Shoes

Mid Game - By now you should be starting to gank a little more, and you should have gotten your Will of the Ancients. After you have got this you should definatly start ganking and helping lanes if you already haven't, helping you pick up kills and assists for your team. By the end of mid game (25 - 35 mins) you should have your Rylai's Crystal Scepter and your Rabadon's Deathcap.

Late Game - By now there should be lots of team fights going on, you should be constantly harrassing and waiting for a good time to engage and pop your ulti for the stuns. You should have almost completed your build if you already haven't.