Starting Items Explanation
The various starting items listed before are the optimal options for nearly any scenario, and since Mister Kennen is such a safe and dominating laner, the 9% Spell Vamp from runes and masteries is all that is needed for sustain and he does not need to hoard health potions that you see many people doing nowadays. Mister Kennen can farm and harass from long range with his Q (as it has 1050 range, which is almost double the range of most AD carries auto-attacks), he has high mobility with his E, and he is guaranteed a stun with a combination of all his abilities, which can be used to escape or harass. As a result, I believe his starting items should be used to prepare for his main items rather than supplementing his laning phase, the only exception is if you go against someone that can lane just as well or even better than Mister Kennen.
Will build into Ninja Tabi (
), Aegis of the Legion (
), or Seeker's Armguard (
). Build this pretty much always if you are against a physical damage-dealing top laner and jungler.
Boots of Speed
Not the most optimal start anymore, as with the Pre-Season 3 patch they buffed every Champion's movement speed and nerfed the actual movement speed you get from the boots, which is why you see people doing ridiculous starting items like a Crystalline Flask (
) plus a ton of potions. Honestly, I still don't mind going Boots of Speed for Mister Kennen as even if it's not as much movement speed as before, it is still movement speed and it gives the squirrel even more mobility for escaping, chasing, and kiting (press E and run away, then Q and W your enemies!). This is also a safe start if you are unsure of what to start or upgrade your boots to.
Elixir of Fortitude
Kennen's auto-attack harass is strong and this supplements it even more, but the main reason you go for the Elixir is the 100+ instant health which can be the difference between life or death. Keep in mind that the Elixir gives more health than the amount of damage that Ignite can do for many levels, and can save you from being finished off by that. Buy this over Cloth Armor and Boots of Speed if you expect the enemy laner, enemy jungler, or even you to be very aggressive early. Keep in mind that now that it is worth 350 gold (as opposed to 250), which means it is more of a risk to take now and it might not even be worth it since it costs more gold than what you get from a kill (unless it was a spree or first blood).
Rainpwny's Early Faves Explanation
Kage's Lucky Pick
Gold generation items in general has always been favorite items of mine. I use to always build a Kage's Lucky Pick on every AP that I played back when it built into Deathfire Grasp (
). At the time that I am writing this, a patch just came out which changed the item recipe of Will of the Ancients to actually build out of a Kage's Lucky Pick now instead of a Blasting Rod, which makes it a viable early item for Mister Kennen. You will most likely not build Will of the Ancients until very late into the game (your 4th, 5th, or 6th item), but the gold generated by Kage's Lucky Pick can be very useful if you are behind in farming, and if you are ahead the gold will just make you even more ahead, IT'S WIN-WIN I TELL YOU. If you don't plan on buying Will of the Ancients or if your team can't make use of it, it may be better to just skip Kage's Lucky Pick.
This item is a must have. It costs about 300-400ish less gold than Haunting Guise while giving overall more AP and similar defensive stats (armor instead of HP of course), unfortunately you lose the magic penetration side of things but this item will put you on course to building a Zhonya's Hourglass, which is core on Mister Kennen.
Still a good item for Mister Kennen. I personally don't get it because I like to get my Hourglass ASAP. But the few times I decide to get it has proven to still be REALLY strong. The 21% Spell Vamp with runes and masteries is simply insane. If you are getting harassed hard, then get it, otherwise an unnecessary item.
Getting some Doran's Blades on your first return is actually NOT that bad, as you will be auto-attacking a TON (to harass or to farm) and getting one or two of these makes your auto-attacks and Electrical Surge stronger, you also get slightly tankier, and you will make use of the sustain very very well. Personally I don't get Doran's items in general (other than on AD carries) as even though they are very good and cost efficient, I just love getting started building on my core items as soon as possible instead of investing on items to assist the already strong laning.
One Core Item to Rule Them All
This is the big costly item that gives you a ton of AP and Armor in addition to an active that can make or break team fights. You can use the active on this item right AFTER using your ultimate and your ultimate will still be storming away while you are invulnerable and untargetable! Furthermore, it provides many different avenues to save or prolong your life. If various champions like Caitlyn, Karthus, Zed, Vladimir, Morgana, Fizz, Fiora and so on decides to use their ultimate on you, you can just use Hourglass right before the damage hits and you take no damage as a result.
The active is just too good, and the Armor and AP is just icing on the cake for the AP Bruiser Mister Kennen.
And with it now building out of Seeker's Armguard, which is good cheap early-game tanky AP item, you can be sufficiently tanky in nearly all stages of the game now!
Semi-Core, because you'll probably still buy these items anyways
Rylai's Crystal Scepter
A very very very good item on the already CC-heavy Mister Kennen. Not only do the stats help greatly in the makings of an AP Bruiser, the passive is what will make you a straight up monster. The slow from this item that procs with your abilities allows you to stick your opponents even more, which means you can hit your shurikens easier. Combined with your stunning capabilities, Rylai's will make it really hard for anyone to escape your grasp. Additionally, you are even more disruptive in team fights and are more likely to land a full ultimate as a result. The item also synergizes with Liandry's Torment (
), whose passive will deal double damage due to the slow. To be honest, this item IS core on Mister Kennen, but I am a rebel who will not label it as such.
A good item for AP Bruisers as it gives AP, MR, and will reduce enemy MR. The only thing that makes this Semi-Core is if the enemy does not deal much magic damage at all, which means you are better off building a Liandry's Torment, Sorceror's Shoes, and/or Void Staff for your Magic Penetration and AP needs. YOU will be in the middle of the enemy and with Abyssal Scepter's ~700 or so aura range (which is actually larger than your ultimate), you will likely reduce the magic resistance of most of the enemy team in a fight and thus every one on your team is happy as the enemy team is shredded to oblivion.