This is my Guide to playing Kennen, i find that building kennen this way can lessen any damage kennen takes by both physical and magical damage all while maintaining very good ability power damage. Keep in mind that i play kennen as a team player the way he should be played. this is for setting up kills for the team and giving your team an edge in team fights. that doesnt mean that you wont be dealing damage out yourself. but its the team fights where you really shine.

Obviously in this build u will find things that can be interchanged with one another for example in my rune selection i chose armor runes over magic resist. i chose that mainly because i myself run into more people stacking AD rather than AP during the duration of the whole game. just in case i do end up stacking different items that will give me armor and magic resist as well i just saw that there were more items that can give me Ability power along side magic resist instead of ability power along side armor. so i chose to go with runes to help armor so id be pretty stacked on both ends.
another thing about the build is the purchase order when it comes to abyssal scepter and zondas hourglass. those two are also interchangable i usually buy what every i need first depending on if my opponent is going AD or AP, and what lane i am in usually i am going mid with kennen so id get abyssal scepter to give me that added magic resist to help but in other cases when im forced to go top in the beginning or the opposing mid champ is someone like ashe or someone who does AP id go with zondas hourglass for the armor.
i would say if i were to make any more adjustments the item build would be to find items to add more magic penetration, if you find that your opponent isnt dealing much damage to you in the first place then you can replace the mercurys treads for sorcerers shoes for the added magic penentration, because you will often find people stacking magic resist against you because of kennens high ability power. so stacking any other magic penetration items would be a good thing to add to kennen.

Kennen is a good farmer in my opinion. all you need to do is keep a fair distance and get those last hits while harassing the enemy. use your Q whenever its up to harass and make your enemy back off the farm and continue farming away. doing that might cause the opposite team to attempt for an early gank if that does happen use his E ability to get out, but other wise try not to play overly aggressive. just poke and back up and farm only going for the kill when you know u can.

Kennen is a really good Team fighter getting in the fight and out in good timing is what you need to do to play this champ well. you do not want to initiate when you play kennen because he is squishy. what you want to do is be in the back of the fight but come in like third or fourth if that makes any sense. i usually stay back and wait for one of my team mates which could be a tank to go in and initiate the i go in after everyone focus fires him and pop my ult when everyone is around followed by my W which hits everyone who go hit by the ult then i use my E to escape outa there. by doing that everyone on the opposite team should be fairly weak. enough so that either my team mates or myself could pick up any kills with my Q. you just want to go in do yor damage and dip out when you play kennen he is good at doing that. that way you will stay alive longer all while being effective.

one thing that i say this build has over others would be that it offers a less squishy kennen that gets the job done. you dont have to sacrifice your damage output either so thats what makes it great. also that this guide is adaptable and that u can change one or two things in the build to make the game totally easier just by switching the order of two things. since no two games are the same i like that this build helps with all kinds of situations other than just focusing on one, with my experience playing this build you can play against both AD and AP champs and not have to worry so much about the damage they can do to you, you can play top or middle it versatile.

Pros: All around better defense
High ability power and magic penetration

Cons: this build requires to know when to build what in certain situations.