Summoner Abilities
Cleanse/Ghost, Cleanse/Flash
I prefer Ghost, mainly because it covers more ground and lets you play reckless even after you've cast it, but some people swear by Flash because it helps you more against ranged DPS. It's all playstyle.
Edit:
statikk always ran Clarity, and he also functioned fine in sidelane. I could never pull that bravery off because I love Cleanse. I'm not sure if he swapped it out based on opposing heroes.
Masteries
0/9/21 non-negotiable. He needs the summoner spells (esp. Cleanse), he needs buff duration, he needs meditation, and he needs SoS.
Runes
You have flexibility here based on your preference. I run MPen Quints and Marks, mana regen per level Seals, and AP per level Glyphs, with one MPen Glyph to let me hit 15 MPen. Some people like having Flat AP Quints instead.
Skill Order
Depends on matchup and whether you're in a solo lane. For instance, you level E against Sivir because Q is garbage. Also if you're conceding lane (died once to MF, or you need to creepclear vs Nidalee) you're better off leveling E over Q, because it lets you farm significantly faster. However if you think you can win the lane, leveling Q is good because with 700 range you'll knock around a lot of heroes. Beware: as of 11/4/2010 at higher Elos it's become significantly more difficult (if not impossible outright) to harass ranged DPS out of lanes because of triple D-Blade shenanigans, so it's probably better to just give up Q and focus on creep-clear and jumping around killing people. Also a W at level 2 is nice because you can get back a lot of mana this way.
Items
Very easy. Open Doran's Shield - doesn't need as much mana because of W, his laning power is more dictated by his HP. Then you want to open Catalyst. The only alternative to this is if you're side-lane and you're not doing horrific on mana, then you can open Soulstealer instead and work your way to Tears/GA/Arch or something like that. Be aware that Cata is as efficient EHP-wise as GA, though, and can also solve your mana issues, so it's preferred. That's not to say Tear/GA is not good - Tears is a stronger pure mana item, and one of the best Kass players before he retired (became an intern) basically swore by SS/GA while running Clarity. After Cata you have a lot of options, such as Zhonya (GJ style), Soulstealer, finishing RoA, making Banshee instead, etc.
Playing him
He's a poking initiating nuking snarebot, that can also get anywhere he wants to ward (pretty safe warding) and can push lanes/towers like a boss. There's almost nothing you can't do with Kassadin, so this is entirely your playstyle. I play him as a tanky initiating poking snarebot, generally de-prioritizing actual damage output (hence not getting ZRing as fast as people like GJ) - most people don't, they play him like this whonky terrible-burst (only two nukes) nuking vulture but hey, whatever floats your boat as long as it works.
Pandonetho Kassadin
+ Show Spoiler +
The Void Walker
http://www.leagueoflegends.com/champions/38/kassadin_the_void_walker
Personally IMO one of the best KSers in the game, and we all already know he's good at taking out squishies.
Summoner Abilities
Generally when I play Kass I take Smite and Flash. Most people prefer ignite to guarantee a kill on an enemy but it's up to you really. Smite gets useless late game besides stealing neutrals but I find it really helpul for farming early game.
Masteries
I take 9/0/21
Runes
Flat Cooldown Glyphs for the 5-6% added with masteries will equal nearly 15%.
Magic Pen Marls and Quintessence for 8.5 penetration.
And flat MP5 seals for the early game.
Skill Order
Simple. Q first for last hits, then E whenever possible, until it maxes out. Then just max out your Q (and getting your R whenever possible of course) and W is last because it's useless for any AP Kass.
Items
The item order is really easy. Out of all the games I've ever played as Kass my most favourite item set happens to be
1 - Deathfire Grasp
2 - Sorc Shoes
3,4,5 - Archangels Staff
6 - Zhonya's Ring
Playing him
Alright so I don't claim to be a really good player or anything, but I do main Kassadin and I feel I'm pretty good with him. Now I'll explain my choices in summoner spells and stuff.
I pick smite because when I lane, I kill 100% of every tank minion that comes, with no trouble. I try to melee minions to save mana whenever the opportunity presents itself but otherwise I'm pretty conservative overall about using mana to kill minions. With this build it's imperative that you get a decent amount of minion kills because the first item that I usually get is either a meki pendant, sapphire crystal, or ability tome. It really doesn't matter, because it's all used to build your deathfire. Levels 1-6 is a pain in the ass if you're not in mid, because prior to it it's really difficult to kill anyone without running out of mana after blasting a null sphere and a force pulse and then dying because you're slow as hell while Garen spins you to death.
So basically I sit around and try to last hit minions as much as possible. Depending on how your laning phase goes, if you last hit really well, and think you're ahead in the money count, go ahead and get a deathfire. However, I usually get my boots somewhere in between. Once you have deathfire and sorc shoes you should try to gank someone or actively attempt to kill people so that you can get some more money. I still find that I run out of mana really quickly at this point so I still play conservatively and look for KSes (which is how I play lol). After getting a Tear mana should become relatively steady and shouldn't drain too fast from fighting people, since a rift walk in, combo, and rift walk out will drain nearly all your mana without any mana items. After your first archangels just go around and try to kill people. It shouldn't be too hard, but you're still extremely reliant on your allies at this point because your AP isn't at a high enough number yet. Just keep playing it safe and target all the people you should be targeting in any team fights.
As the game goes on it should be increasingly easy to farm as you just pulse a minion wave and it should disintegrate all of them, except for the tank minions and sometimes the melee minions. If you manage to get to the point of 2-3 Archangels you're starting to become really powerful. There isn't much to say about Kass except to do what he does best and keep taking out squishies. Remember to always use deathfire first. At level 3 your Rift Walk should be at a 2.8 second CD, from 4 because of your CDR runes and deathfire + masteries. This should make escaping extremely easy, added with the fact that your mana literally takes up to 6-7 consecutive rift walks to actually deplete. Once you get a Zhonya's ring it should be over for ANY one who doesn't have sufficient MR. You'll be toting around 800 AP and your force pulse and null sphere should easily be doing over 1000 damage each, along with Rift Walk doing probably around a base 500 (I'm going off my memory here). Deathfire grasp will do around 58% of your target's max HP in magic damage, and whatever is left should be easy enough to take out with Q + E.
Mind you, this build is for teams that have guys that don't pack a lot of MR. Even with a Banshee's veil someone like Ashe will still take loads of damage if not outright die from your combo. The key factor in winning team fights is either 1 of 2 things.
A) You KNOW you can take out a guy in 1 combo, so if you know this, initiate and take him out. 2.8 seconds later you'll be gone (unless you get CC'd to death but if you're coordinated with your team, they should already be in the fight the moment you initiate.
B) You know you can take them out if they're at half HP or so, in this case let whoever your main initiator is, initiate, then jump in and take them out. The reason why I pack flash is that sometimes 2.8 seconds is STILL too long and with a build like this, you'll die really fast. The risk is in killing your opponent before they kill you.
I've personally gained a lot more love for this build ever since I've started killing Tryndamere's so fast that they haven't had the physical reaction time to even activate their ultimate.
Anywho, that's just my personal experience with this build, and after experiencing a lot of different builds I feel this is the build that is most fun to play, and is effective too. However, if there is an enemy Kassadin who gets Abyssal Scepter, Banshees, Rod or Lich Bane and such, you'll probably be screwed because he'll do way more damage to you than you will to him. Wandering off into bushes is the most dangerous thing to do since any pair of capable damage dealers with CC will take you out fast, but otherwise, with 2000-3000+ mana and insane mana regen you will have no trouble constantly chasing, or escaping anyone. Your damage output will be huge, even in the face of some basic MR (like Banshees on a carry), and deathfire is just insane with the amount of AP you have. An additional 28% (added to the base 30%) damage from your 800 AP alone.
Otherwise, have fun with it. Levels 1-6 are a major pain in the ass, but after that it picks up. I find Anivia to be an extremely good laning partner as the 2 nukes can deal some serious early game damage and sustain each other (if Anivia takes clarity that is).
http://www.leagueoflegends.com/champions/38/kassadin_the_void_walker
Personally IMO one of the best KSers in the game, and we all already know he's good at taking out squishies.
Summoner Abilities
Generally when I play Kass I take Smite and Flash. Most people prefer ignite to guarantee a kill on an enemy but it's up to you really. Smite gets useless late game besides stealing neutrals but I find it really helpul for farming early game.
Masteries
I take 9/0/21
Runes
Flat Cooldown Glyphs for the 5-6% added with masteries will equal nearly 15%.
Magic Pen Marls and Quintessence for 8.5 penetration.
And flat MP5 seals for the early game.
Skill Order
Simple. Q first for last hits, then E whenever possible, until it maxes out. Then just max out your Q (and getting your R whenever possible of course) and W is last because it's useless for any AP Kass.
Items
The item order is really easy. Out of all the games I've ever played as Kass my most favourite item set happens to be
1 - Deathfire Grasp
2 - Sorc Shoes
3,4,5 - Archangels Staff
6 - Zhonya's Ring
Playing him
Alright so I don't claim to be a really good player or anything, but I do main Kassadin and I feel I'm pretty good with him. Now I'll explain my choices in summoner spells and stuff.
I pick smite because when I lane, I kill 100% of every tank minion that comes, with no trouble. I try to melee minions to save mana whenever the opportunity presents itself but otherwise I'm pretty conservative overall about using mana to kill minions. With this build it's imperative that you get a decent amount of minion kills because the first item that I usually get is either a meki pendant, sapphire crystal, or ability tome. It really doesn't matter, because it's all used to build your deathfire. Levels 1-6 is a pain in the ass if you're not in mid, because prior to it it's really difficult to kill anyone without running out of mana after blasting a null sphere and a force pulse and then dying because you're slow as hell while Garen spins you to death.
So basically I sit around and try to last hit minions as much as possible. Depending on how your laning phase goes, if you last hit really well, and think you're ahead in the money count, go ahead and get a deathfire. However, I usually get my boots somewhere in between. Once you have deathfire and sorc shoes you should try to gank someone or actively attempt to kill people so that you can get some more money. I still find that I run out of mana really quickly at this point so I still play conservatively and look for KSes (which is how I play lol). After getting a Tear mana should become relatively steady and shouldn't drain too fast from fighting people, since a rift walk in, combo, and rift walk out will drain nearly all your mana without any mana items. After your first archangels just go around and try to kill people. It shouldn't be too hard, but you're still extremely reliant on your allies at this point because your AP isn't at a high enough number yet. Just keep playing it safe and target all the people you should be targeting in any team fights.
As the game goes on it should be increasingly easy to farm as you just pulse a minion wave and it should disintegrate all of them, except for the tank minions and sometimes the melee minions. If you manage to get to the point of 2-3 Archangels you're starting to become really powerful. There isn't much to say about Kass except to do what he does best and keep taking out squishies. Remember to always use deathfire first. At level 3 your Rift Walk should be at a 2.8 second CD, from 4 because of your CDR runes and deathfire + masteries. This should make escaping extremely easy, added with the fact that your mana literally takes up to 6-7 consecutive rift walks to actually deplete. Once you get a Zhonya's ring it should be over for ANY one who doesn't have sufficient MR. You'll be toting around 800 AP and your force pulse and null sphere should easily be doing over 1000 damage each, along with Rift Walk doing probably around a base 500 (I'm going off my memory here). Deathfire grasp will do around 58% of your target's max HP in magic damage, and whatever is left should be easy enough to take out with Q + E.
Mind you, this build is for teams that have guys that don't pack a lot of MR. Even with a Banshee's veil someone like Ashe will still take loads of damage if not outright die from your combo. The key factor in winning team fights is either 1 of 2 things.
A) You KNOW you can take out a guy in 1 combo, so if you know this, initiate and take him out. 2.8 seconds later you'll be gone (unless you get CC'd to death but if you're coordinated with your team, they should already be in the fight the moment you initiate.
B) You know you can take them out if they're at half HP or so, in this case let whoever your main initiator is, initiate, then jump in and take them out. The reason why I pack flash is that sometimes 2.8 seconds is STILL too long and with a build like this, you'll die really fast. The risk is in killing your opponent before they kill you.
I've personally gained a lot more love for this build ever since I've started killing Tryndamere's so fast that they haven't had the physical reaction time to even activate their ultimate.
Anywho, that's just my personal experience with this build, and after experiencing a lot of different builds I feel this is the build that is most fun to play, and is effective too. However, if there is an enemy Kassadin who gets Abyssal Scepter, Banshees, Rod or Lich Bane and such, you'll probably be screwed because he'll do way more damage to you than you will to him. Wandering off into bushes is the most dangerous thing to do since any pair of capable damage dealers with CC will take you out fast, but otherwise, with 2000-3000+ mana and insane mana regen you will have no trouble constantly chasing, or escaping anyone. Your damage output will be huge, even in the face of some basic MR (like Banshees on a carry), and deathfire is just insane with the amount of AP you have. An additional 28% (added to the base 30%) damage from your 800 AP alone.
Otherwise, have fun with it. Levels 1-6 are a major pain in the ass, but after that it picks up. I find Anivia to be an extremely good laning partner as the 2 nukes can deal some serious early game damage and sustain each other (if Anivia takes clarity that is).