I'm going to have to disagree with aborted on a few things, such as the Soulstealer. I have had TONS of success with kassadin without ever putting a dime into a soulstealer. I think the guy looks pretty good to me, just add some pictures and all that mumbo jumbo in there. although i feel that lich bane would be a good addition to it, if your into that kinda thing. +1

Thanks for the advice... i see the build is primitive. As the "notes" section stated- "the build will be updated". Please, its very late... I forgot many things :P

The build is primitive, but gives a general idea of what you're supposed to be doing as Kass. Not finished enough to up-vote it, and the item sequence is, IMO, off.

I would suggest getting teleport, because getting to the fights with Kass or split-pushing at a key time is one of the strongest things about him.

He also is very vulnerable; I would suggest getting a Banshee's over an Hourglass. The protection from that single key CC can make or break a teamfight for him, especially with his ability to escape late-game. Also, he's a very strong snowball character, and any guide should have a Soulstealer in it as core, winning OR losing. I can't count how many games I've been able to rescue out of the toilet because of the extra damage I've gotten from those key teamfights, walking away with 6+ stacks.

My suggested item build would be
Tear > Catalyst > Boots of Speed > Soulstealer > Sorc Boots> Banshee's > Archmagi > Deathcap.

Dude...why 2 rabadons?.There are far better choices...seriously.And you will die like a leaf.