Not a fan of that build. There are far better all out AP carries in LoL. Specifics that I disagree with: Ghost: not needed, you move SO fast already. Flash is too powerful of a summoner spell for you not to take. Sorcerers shoes: Meh, I prefer to get boots of swiftness. It makes you faster when you are using Lightning rush so you can tag all the creeps/champs you want. Also makes for better chasing/fleeing without needing ghost. Will of the Ancients: This is an OK item, but I don't think that it is that great on Kennen. I'd get the hextech revolver and then keep it while you build your Rylais. Rabadons: You're not an AP nuke. Zhonya's is a far better item on Kennen, because you can activate it while your ult is stunning everyone. I can't justify buying energy regen yellows when most characters I play won't make use of them. However, if you do get these it seems silly not to get a little cooldown reduction via your glyphs. Personally I've got flat armour seals, and then half and half cooldown/AP glyphs. Ultimately, it is down to individual playstyle, and what exactly you are aiming to get out of Kennen. For me, I'm a perma-stun/slow champ who will kite you to the ends of the earth, and very rarely die. I'll jump into a teamfight a split second after the tank, stunning the whole enemy team (and a few of them a couple of times), knock everyone's health down by a third or two, and let the hard carries sweep up. That's not to say if you want to build him as a hard AP carry though.