Comment listed above.

Your items section is pretty jumbled up, almost to the point where it hurts to read, and a lot of them don't make any sense. Things like Thornmail are a terrible idea on Kassadin. You're not a tank, you don't want to have damage return, you want armor and side bonuses from things like frozen heart. Nashor's and Guinsoo's are for hybrids. Kassadin is a mage. Especially with his recent change to his W.
You don't explain how to play Kassadin, you don't really talk about anything other than items, and even then you just restate the item's stats or say "You know you want it".
Gunna have to be a -1 from me.

-1 just for the vote

Lolwut?

"*Nashor's tooth - Not bad especially for hybrid buidls] Nashor's tooth - Not bad especially for hybrid buidls"

"or R > W > E > Q thats for hybrid builds with items like Guinso or Nashor tooth."

You can't be serious... Kass is a supernuke. The only nuke that can escape after finishing your destruction. If you melee, especially without any items like Zhonya's or an Abyssal Scepter, or even a Banshee's, you will die so fast that you W won't be cast twice. Your E is only to charge your W. You should also get more AP heavy items. Your null sphere should chunk out Hp from you victims. Even trying a hybrid build is just asking for a 10 death game, especially without stacking health/armor/MR. Lets not be stupid here, Morello's? A deathfire grasp makes more sense.

-2