Hi everyone,
welcome to my Kassadin guide on Mobafire.com

I am German so English is not my mother tongue and I am sorry for all mistakes.

This is my first guide and I'd like constructive critism and if you like this guide pls vote it up.
This guide also includes a little bit theory crafting.
EDIT: I am sorry but I couldn't find the button the include Items, Summoner Spells and Runes :D if you know where I can add it feel free to comment!

Pros of Kassadin:

-Good harassing power in laning
-High damage in mid and end game
-Extremly powerful against any AP MID
-Good escaping abilitys

Cons of Kassadin:

-Quite squishy
-Focused in teamfights
-Often banned in rankeds

In general: I am a fan of magic penetration!

Because of that I use Quints and Marks of Insight.

For Seals I take armor because the biggest problem you could get is a AD MID as an alternative you can use flat hp.
EDIT: For extra mana regen you can use mana regen seals. I'd advice to take flat mana regen because in endgame if you are not stacking ult to much mana shouldnt be a problem.

And finally for Glyphs I take flat cooldown reduction making you harass faster.

For Masteries I just use 21/9/0.

I dont use 21/0/9 because I take the extra armor hp/lvl and flat hp, on top of that I get that Cleanse update.

EDIT: If you know you wont get an AD MID you can choose 21/0/9 taking mana regen. Also if you dont take cleanse you shouldn't invest the 9 points in defense on cost of survivability.

You should be maxing Null Sphere first and take a point in Forse Pulse in Level 2 and 7 and then max it next. You just get one point in Netherblade in Level 4 and max it last.
Of course you take your ultimate whenever posible.

You can take most summoner spells without getting problems but I'd prefer Flash and Cleanse.

Flash: Flash is always good, best use is for early tower dives ( Lvl 6+ ) and then just ult in -> burst down -> flash out. And of course if you get ganked with CC you can just flash and then ult out with low health.

Cleanse: Free Quicksilver Sash. If the enemys have much CC take it! BUT it's just usefull if you can manage it to use it in that 1-2 seconds of stun!!

Exhaust: It reduces the damage done by enemys ( good for early 1on1 ) and it's helpful in teamfights but in general your team should have enough exhaust without the AP MID taking it.

Ignite: 500 Absolute Damage is always nice! Of course you should take it if the enemys have a Swain or Fiddlesticks!

Teleport: You can go to defend tower faster, port to wards and gank or you can just go back and buy some stuff -> always good.

The longest part of this guide.

After the Core ( Soccerer Shoes , RoA, Rabbadons ) you should be getting items depending on the enemy team.

It's said in almost every guide and I will repeat it:
If you are dead you deal no damage!

If
-the enemys get much CC get Quicksilver Sash.
Quicksilver Sash is nice if but it's like cleanse: If you can't manage it to press that button in the time stunned it's a waste and you should get a Banshees Veil instead.
-the enemys are heavy AD get Zhyonas Hourglass
Zhyonas Hourglass offers a huge load AP, armor and on top of that a fantastic active! you can use it if you get focused and still have that 1 second cd on your ult...
-the enemys are heavy AP and you got enough damage output get Banshees Veil
Banshees Veil is a overall great item. Extra Health,Mana,Magic Resistance and it's fantastic passiv. It can save your *** if you escaped and then an i.e. Requiem comes in ;)
-the enemys are heavy AP and got magic resistance get Abyssal Scepter
Well AP and magic resistance and magic penetration. 3 nice stats at quite low costs.
-the enemys are heavy AP and you still lack damage get Lich Bane
Lich Bane. One of my favourite items because it makes you an op tower pusher: Ult-Autoattack-Autoattack..-Ult... it increases your damage output and adds that missing 500 damage if you dont have ignite to finish off someone.
-the enemys have much health get Deathfire Grasp ( !activate at beginning of fights! )
Well lets say an enemy has 3k health and you lets say got 450 AP.
Deathfire Grasp will do 3000/100*39 = 1170!! damage. That's more then ANY of your spells does at that moment. Since an enemy has more then 1282 health Deathfire's active will do amazing 500 damage! Like a 5. spell...
-the enemys stack magic resistance:
-some enemys have got more then 84 magic resistance get Void Staff
-else get Abyssal Scepter
Theory Crafting:
-enemy has 50 Magic Resistance:
50mr-34mPen(14 by runes + masteries, 20 by soccerer shoes)=16 mr left
16-20( abyssal scepter ) = -4mr! means you will deal extra damage!
16-40% = 16-(16/100*40) = 16-6,4 = 10mr! means he will still block damage
-enemy has 84 magic resistance
84mr-34mPen = 50mr left
abyssal scepter:
50-20 = 30 left
void staff:
50-40% = 50-(50/100*40) = 50-20 = 30 left
-enemy has 100 magic resistance
100mr-34mPen = 66mr left
abyssal scepter:
66-20 = 46 left
void staf:
66-40% = 66-(66/100*40) = 66-26,4 = 40 mr left
-you could see: at 84 magic resistance it doesnt matter what item you get,
before it's better to get abyssal scepter.

EDIT: Demon Cleaner commented that I should add Archangels because if you stack ult really much you get mana problems. I used to be a fan of Archangels but it's just a viable choice if you are not getting focused resulting in not having a big need in survivabilty items.

How to behave if you get an AD MID that even ****s you up if you silences him?
Well he can outfarm you quite easy in the beginning because you can't just go in range -> null sphere him -> walk out. He will just follow you and take about 50% of your health... You have to play really defensive if you play against an AD MID until level 6! If you got ult just Ult + Q + E -> 70% up to 80% of his health are gone instantly. Then you either can Ignite / Exhaust him if you got it OR you run out and in 15 seconds you repeat this. He will be dead and you will be at about 50% health.

Of course it's helpful if you have a jungler in your team who can gank early and hard so the enemy AD carry will be on lower health then you are.

I like playing ARAM and if you get Kassadin it's not always the best choice to get your Null Sphere before you get your Force Pulse because it's the same scaling and basic damage but Force Pulse is AOE!

I hope you enjoyed reading this guide!
As soon as I know how to add pictures I will do it :D

In the end I wanted to give something back to the community because I learned so much about some chars here when I just started playing LOL!

If you have any suggestions on how to improve this guide ( besides adding pictures ;D ) just leave a comment.

I hope you have some fun with Kassadin and will pwn with him.

NOTE:
Because many guides got voted down without any comments left I enabled the "Require comment to vote" option.

MfG

Defunto