I started off playing Kassadin because my friend told me how good he was. To be honest, at the start he was not my cup of tea. I didnt understand how he worked or how to build him and how to utilize his ultimate. I decided to stop playing him as well as the other AP champs I used. Then I hit level 30 and every third match I saw a Kass, some were bad just like me, and some where amazing and they melted me easily every time. This is when i started to play him a lot more. I spent a while in bot games trying to figure him out (even though they dont give you the exact experience or even close to that of playing real people). Eventually, after finally reading and realising what was happening if i continuously spammed his ultimate I began to decipher what items where good on Kass. This is where the build begins, please leave a comment at the bottom telling me how to improve etc.

I know I will more than likely receive criticism for my rune choice, considering it is ALL flat AP. The reason I choose to take the flat AP runes is because I begin the game off with a decent amount of ability power which can lead to a fantastic early harassment gamestyle. I am not saying go and buy pure flat AP runes, go by your preference, if you prefer magic pen and mana and AP + CDR go for it but I believe his spells have a low enough cooldown as it is.

Once again runes are purely your choice, I just prefer the flat AP.

When I am playing Kassadin I tend to max out his Force Pulse first, but i take the original point in Null Sphere. I wait for level 4 to take nether blade, I hardly EVER activate this spell unless I am charging my E (Force Pulse) at an early level, I use it simply to stay in lane for longer periods of time drawing mana from it. Obviously I take a point in the ultimate where ever available (6 - 11 - 16.)

Kassadin uses A LOT of mana I found once he hits level 6, for that perfect getaway his ultimate comes in handy heaps, unfortunately, spamming it means every time you use it, it costs more mana, so i take tear of the goddess straight after my boots and dorans ring. Then i build the standard AP items such as Rabadons for the extra % of AP and a void staff and sorcerers shoes for magic pen (another reason I don't take the magic pen runes). Then I add the abyssal scepter into the mix for reducing their magic reduction as well as boosting my own to work with my passive.

Now some people may be more confident within themselves and take a Mejais instead of a dorans ring, so instead, buy an amplifying tome and good luck to them on stacking.

As i finish off my build I sell my Dorans and this is where I grab the void staff for extra spell penetration.

For summoner spells i take the stock standard flash and ignite,
I take flash for early game getaways / gank attempts while I dont have my ultimate.
Ignite and it's mastery so that I can gain the extra 10 AP for early game kills to avoid diving as well.

Masteries, I believe, are your call as well as your summoner spells. It all comes down to personal preference, I take 10/0/19 masteries just based on how I play Kass.

Thank you for taking the time to read and hopefully use this guide =] Please comment and provide feedback =]