Hai yall, my name is *COUGH* i'm not going to tell you anything about me, my dad would get mad about privacy stuff or whatever. I'm only going to tell you my summoner name: Junkyarddude. I play on NA server and as i write this guide, i am currently in Bronze IV. Now, i know what you are thinking "This guy is bronze, why would i listen to such things?" (actually, i don't know what you are thinking), but please read on and laugh at my n00biness, this is my first guide, so laugh all you want, especially since i don't know how to add images. "It'll be fun!" -Quoted Annie, the Dark Child
Good Fun Have Luck
WARNING: THIS GUIDE IS VEEERY LONG, YOU MAY NOT READ IT ALL IN ONE SITTING. YOU MAY ALSO NEED TO READ IT MULTIPLE TIMES TO DIGEST THE INFORMATION, GOOD LUCK SUMMONERS. Also, this summoner does not know how to add images, please excuse him for he is in bronze.

Pros:

Very good at stealing *Clears Throat* Securing kills
High Damage & Assassination Potential Late Game
Can split push & Backdoor
Quite Tanky lvl 1 vs. mages due to passive
Arguably the most mobile champ in the game
Easy to farm with w, e, and r, and auto-attack (w passive)
Very annoying to enemy

Cons:

Very bullyable (is that a real word?) early game, especially vs AD Assassins
Melee/Short ranged
Not much burst early
Very Annoying to teammates (IF you steal their kills, which i advise)
No CC, outside of slow.
(Un)Commonly banned

Flash and ignite are my choices

Summoner spells are personal preference, some people take ghost, but i prefer ignite for Kill (Stealing) power, and flash for unexpected flash ulti surprise yur ded plays.

I've been testing out builds for kass ever since he got reworked since people stopped using him, and ive found this to be pretty effective. I max w and get lich bane and it seems to work out really well. Altough this build is weak early game, if you are good at csing (in which the w passive will help you in), you can farm until you get your sheen (not neglecting good roam opportunites, dragons, barons, passing n00blord teemos, and cs of course) and kill the heck out of them all (im talking about the minions, of course, kill them all). You will notice that w does quite a lot of damage once you get sheen. I was motivated to play kass when he got nerfed, and wanted to show people that it was not a nerf, rather, a buff to his overall assassination powers.

Void Stone is Kass' passive. It helps when laning against mages, because you take reduced magic damage, allowing you to farm to your hearts content (not really). Since My Kassadin is focused on farming up and not dying early game, this passive is amazing. It also allows you to go through minions, and not get creep(b)locked.

Null Sphere is Kass' Q. It fires a ball of purple void energy at target enemy champion, minion, or neutral monster. It also gives you a shield that shields you of magic damage for a short period of time. This skill along with his passive is why kass is good vs mages. He can ignore a lot of damage from mages when you time your q correctly. It can also be used to farm from a distance if they are harassing you. Dont farm with Q TOO much though, It will drain your mana and the cooldown on q isnt enough to last hit every minion. You can max Q or E depending on matchup. Also, null sphere can interrupt channeled spellls like malzy's nether grasp, and fiss mortune's bullet time. This wil happen VERY RARELY, but keep it in mind when teamfighting or when in skirmishes, it can save you a lot of trouble.

Nether Blade is Kass' W. It is the center of this build, your main damage ability, and your FARMING TOOOOOL!!!!! Its passive gives you extra magic damage on your basic attacks, whihc helps you last hit minions. The active can proc lich bane and do tonsofdamage. Flash ulti w is very unpredictable, and it (steals) kills very well. Use it to farm until lich, use it to do tons of damage, use it to win. Max first

Force Pulse is Kass' E. It deals AoE damage in a wide cone in front of him. You must have 6 charges to activate this move however. One charge is obtained every time a spell is cast by anyone near kassadin (including kassadin). It also slows any enemies hit. use this to farm many minions at the same time, or use it when someone is ganking for the slow (helps you get away, chase someone)

Riftwalk is Kass' Ulti. This skill is what makes Kass, Kass. Kasadin teleports a short distance and does magic dmaage. Note that this ability scales with maximum mana, rather than ap, so in this build, this does no damage. Purely a utiliy skill that will help you immensely. I can list 80 percent of the uses and take up a whole page (Maybe.....) I will only list a few uses. Chasing, Escaping, Juking, Flash ulting, walking through walls, trying to steal dragon or baron (and failing),stealing kills, and walking into the enemy spawn when you are at the enemy nexus (Dont forget zhonyas, if you have it) are all effective ways to use this skill (except maybe the last one). The more you practice with kass, the more valuable this skill becomes.

In summary, use your w to farm and do tons of damage, use r for everything, q for sustain early, damage mid-late, and e for chasing, kiting and farming.
My Kass is focused on farming, and helping the team out until lich bane and DFG and then doing tons of damage.

Starting Items

When considering starting items, you want to think DEEEEEPLY about the enemy team, and what you want to accomplish. My starting item pool include Boots, Crystaline flask, cloth armor, and rabadon's deathcap. When considering a starting item, think about questions like these:

How much can i farm against this opponent?
Is he harass heavy?
Is he AD or AP? Or Both?
Can i out trade him?
Is he Skillshot reliant?
Do i want to troll this game?
is his damage burst or sustained?
How much damage can he do early? (Not in this exact order of course)

If i were to go against a Kha'Zix for example, (btw kha is my main, my fav champ), i would think, "Kha'Zix has a very High AD burst potential early, but no harass outside of the occasional q to the face. Since i want to focus on survivability and farming i want to be as tanky as posible. i will also take 5 pots so that i can eat any w's he tries to throw at me"
Also consider what you want to max after w in a laning match up. "Since Kha'Zix deals no magic damage outside of his pasive, i will max e because q dosent block much. Also, he has no cc outside of his own slow, so i can escape him when i e and then ulti out of there"
If i were against someone like Karthus, for example i would think "Karthus does high sustained damage, but in the form of skillshots. I will take boots, as well as 4 pots, so that i can outsistain him and gain an hp lead. With my boots i can dodge his skillshots and out trade him."

From here, itemization is completely standard, you get a lich bane, you get a DFG (deathfire grasp), and then a duncecap.

"But why DFG first rather than Duncecap?"

Well, DFG when used before w does alot of damage, go test it out in a custom game.

Situational Items

Again, (i'm going to say this alot) this boils down to personal preference, as well as the enemy team champs and builds.

For example, Don't take Void staff if they are not building magic resist.

Here is a list of items i usually buy:

Void Staff
Guardian Angel
Zhonyas trollerglass
Abyssal scepter

Feel free to buy whatever item you feel like, i honestly don't care. As long as it helps your matchup against your opponent. I want you to THINK FOR YOURSELF. I Don't Care if you go Mercurial, whatever that word is if you have a solid reason, such as the other team having hard cc and you are getting caught out easily. That is the purpose of situational items. They help you adapt to the opposition. So i wont really tell you what to build, just the thing i would usually turn to

Kassadin's early game is fairly weak, you can get bullied easily and poked down due to thet fact that he is a melee champ. At this point in time, you cannot instakill them with your w+lich bane so focus on farming and staying alive and farming like there is no 2moro. A tip i can give you when trading/farming is utilize Auto-attack and then W. W resets the AA (auto-attack) timer so you can do 2 AA's quickly. You can cs under tower with this, as well as cs two minions that are low and secure them both.If possible, AA your foe for some damage when they come in to cs (hybrid pen marks increase damage) Dodge any skillshots thrown at you and try to cs alot. Try to freeze the lane, by only killing a minion if your opponent has killed one. If you do this, the lane will not push, nor pull (pull= opposite of push). BUY PINK WARDS AS THEY HELP YUOR JUNGLER GANK BY ENSURING YOUR OPPONENTS HAVE NO WARDS!!! At lvl 4, your trades become good, just poke them down with your q and w. Try to think about the trading ability of your opponent. If for example, you are vs leblanc, dont trad with her lvl 4, she can instakill you. Trade with her lvl 1 because Auto-attack for Auto-attack, Kass is beeter (Courtes of the w passive). Think about when you opponent is strong/ weak, such as when lb uses her q to farm, I know I can trade. USE YOUR HEAD. Never underestimate a good roaming opportunity, free 300 gold is never a bad idea. HAVE MAP AWARENESS. If you see your jungler getting invaded lvl 2 by the enemy jungler, go over there and 2v1 him with your jungler. If you see bot lane pushed in past the river, and the enemies are somewhat low health (Common in Bronze ELO), go over there and gank! Once you hit lvl 6, you can trade alot better, again, and you also will become ungankable (sorta). You can walk up to them, w-q-e them, and riftwalk away (anther good use for ur ulti). Also, your ganks become a LOT more effective and surprising. At this point in time, you should have your lich bane.

Assuming you csed well, and got a few kills from roams, Kassadin becomes a beast mid-game. Help other lanes once you get your ulti, and secure kills and objectives for your team. MAP AWARENESS IS KEY TO PLAYING KASSADIN (And any other champ for that matter). Help skirmishes around the map. "I'm on my way" -Kassadin. In 2v2 and 3v3 and 4v4 skirmishes, your job is to kill the strongest on their team, you are the assassin right? You can also focus down their assassin because they might be focusing you ADC/ADR. Also, DON'T JUMP IN RANDOMLY, YOU WILL GET FOCUSED DOWN THE DRAIN (AND FLAMED BY YOUR NOT SO GOOD BRONZE TEAMMATES). Only jump in when you know you are safe, such as when you target is out of position (going out to ward, away from teammates, etc. This is common in Bronze ELO), or when the enemy team cannot react. (Cooldowns down, friendlies have used their cc, etc.) Once you kill thier source of damage, go ahead and kill whoever you feel like/can. Remember to stay safe during these fights. Baiting fights out can also help you surprise and catch out an ad carry.

By now, you should be winning all your fights. If you are, after winning a fight, take a tower or dragon (or baron, if your team can rush it down). If you are NOT doing so well, kassadin is a good split pusher because of his w passive and also because he is unkillable when his ult has only a 3 second cooldown. If you are split pushing, tell your teammates to NOT ENGAGE THE ENEMY TEAM (doing it in caps is also a good idea). Disengage is necesary when you are split pushing. While you are split pushing, ward ward WARD! Warding will tell you hen your oponents are after you. IF at least 2 people are after you, tell your team to fight the 4v3 becuase they have a numbers advantage. If only 1 person is after you, 1v1 them and continue split pushing. OR you can run away and try to get to your team before the other erson can and rush a 4v5. Your objective at this point in time is to take towers. Inhibs also help because it forces your opponents to defend a single lane, allowing you to focus other lanes' towers.

I'm not going to teach you how to lane vs every single champ in the game. I'm going to teach you how to analyze a lane matchup. When analyzing a lane matchup, think about questions reguarding their skills. Each champion has seven skills (QWER, Passive, And 2 summoner spells) Analyze your opponents' kits and think about things like these...

How many damaging skills do they have?
Are they skillshots?
What is their range?
How many mobility skills do they have?
How many damaging skills do they have?
How many sustaining abilities do they have?
How many cc/debuff abilities do they have?
Hard or soft cc?
Does He Have displacements?
How long are the cooldowns?
Know what their QWER and passive skills do, EXACTLY!
When are they strong? When are they weak? (Ex: Certain skill on cooldown, not high enough level to have all skills, lacking certain item etc. and vice versa)

Based on questions like these, you should be able to identify what your opponents kits are trying to accomplish. For example, lets say we find our Kassadin against Kha'Zix.
I'm going to analyze Kha'Zix kit by asking myself the above questions. Kha'Zix Has 5 damaging abilities (passive & ignite included), and very high burst, especially when you are isolated. Kha'Zix also has 3 movement abilities in his e and ulti (which can ready his passive for more damage) and let's not forget flash. He has 1 sustaining ability, and only 2 slows for cc. ***ming you know what Kha'Zix's skills do EXACTLY, we can imply that high burst and mobility (resets, not to mention) make Kha an assassin. Kha'Zix is pretty mobile, and can jump on kass t even lvl 2, which makes him dangerous early game, especially since we dont have our ult at this time. Kha'Zix IS vulneerable once he uses his e, so baits (with your jungler, ask for assistance) are pretty effective. Slow him, and then combo him while his skills are on cooldown. He can only Q back. also mind when his passive is not up. Kha'Zix is also weak when he dosent have his q up. Predict when he is going to walk up to aminion and q another. When laning vs Kha'Zix, be cautious and cs well, gain a lead from cs and roams.
Play smart, and use your head, that is how you win your lane. Do this sort of thing when you are in the loading screen.

The way I play Kass, farm and don't die early (especially don't die to LB she'll keel the heck outta you), be smart, get some kills around the map. Mid game, feed your teammates, you should be fed enough to do that. Participate in dragons, skirmishes etc. If you lose your lane, don't give up, farm, and then help your teammates get fedd. Roaming is always a good option, just make sure your tower does not get pushed. Late-Game Assassinate the ADC and other huge, fed people. Focus the most fed in fights, and lastly, BE SAFE AND PLAY SMART.

6-2-2014 Uploaded this guide to MOBAFire
Patch 4.12 Kass Nerfed again??? I knew his w was good