So you decided to check out the snake. Maybe you saw that she had max difficulty and were curious why, maybe you are some kind of pervert that is into snake-women, or maybe you tried to mid against me as Ashe and thought, "Hmmm, maybe I'll try out this Murder Machine!"
The point is, you have come to the right place. I will show you how to build, and more importantly, play the snake (giggity).

All of the items, masteries, and runes will be explained, so please don't just downvote based on the fact that there's a Warmog's Armor in Cass's cheatsheet. (this has been since removed, but I still think it can be viable in some situations)

For the doubters, and since this seems to be the thing to do on this site, here is my resume:Make sure you look at the part that says largest multikill ;)

Pros
Very High DPS
Excellent Range on 2 of her skills
Has 2 aoe dots, a nuking stun ultimate, and a nuking combo with her Twin Fang
Very underrated champion, lots of overcommiting (and therefore dead) opponents
Brings a variety of uses to a teamfight
She slithers, and the animation is really cool

Cons
Very squishy the whole game
Has 2 skillshots, and a hard to land ultimate
Requires smartcast, so if you don't like to use it, tough ****
No escape mechanism when flash is on cooldown
Tends to get heavily focus fired

Pretty standard caster masteries in offense, but I think that my utilities may raise a couple eyebrows.
Good Hands: I used Perseverance for a long time, and any build that had good hands was "garbage noob ****." Truth is, I was garbage noob ****, and I changed my sinful ways after reading this: http://www.leagueoflegends.com/board/showthread.php?t=219077

Awareness: This is a no brainer, but for some reason I see so many Cassiopeia builds not get this mastery. Going mid against someone like Katarina or Ashe, you need to hit level 6 1st, so you can stun them after they try to ulti kill you. (more on Kat later)

Expanded Mind: Extra max mana... I prefer this for the extra early game harrass, and the synergy it has with Tear of the Goddess and Archangel's Staff lategame. Ff you want to, you can pull 2 points out of this one and one from Utility Mastery and put them into Quickness.

Meditation: Extra mp5...nuff said

Utility Mastery: Makes blue last longer (more on this later)

The rest just make sense, and are more or less just down to personal preference

Greater Mark of Magic Penetration: Anything other than MPen is a waste of runes

Greater Seal of Scaling Mana Regeneration: Mp5 because Cass needs it, especially at higher levels. Mp5/level because flat gives .41 mp5. At .065/level, the Greater Seal of Scaling Mana Regeneration overtakes the Greater Seal of Replenishment by level 7. (.065*7=.455) Math Wins.

Greater Glyph of Ability Power: Noxious Blast has a 90% AP ratio, and Twin Fang has a 55%, but strikes twice a second if they cant move. The flat AP is really the best case scenario for her, since Cass doesn't need cooldown reduction (.5 sec cd anyone?) or increased mana.

Greater Quintessence of Magic Penetration or Greater Quintessence of Ability Power: This is really just down to personal preference. Personally I have been using the flat AP Quints, but you can never have enough MPen.

Things That Are Good
: This helps you get a first blood, and the 50% reduced heal is pretty sweet later in the game.
: This is one of those things that makes people scratch their heads and question my sanity. Exhaust on a non AD champ/non tank? Yes. Let me break it down for you: Exhaust + Noxious Blast + Twin Fang + Twin Fang + Twin Fang + Twin Fang= Pwnage
:One of the best spells in the game, what I sometimes call the "get out of stupid card" One hell of an escape mechanism.
: A good alternative to Flash, Ghost is more likely to get you out alive in certain situations.
: 90% of the time, when I die as Cass, it's because I was stunned/silenced/feared. This should help

Things That Are Viable
: Teleport could let you save a turret, get a gank, or get back into lane after b, but honestly this is something a tank should have, not you.
: Some people swear by the glowing eye, and if it can help you avoid a gank or spot a jungler, then good job, use it. The thing is, a support should have this so you don't have to sacrifice an escape mechanism or more offense.
: This is good if you burn up all your mana in the beginning, but it becomes useless later in the game as the Greater Seal of Scaling Mana Regeneration and Tear of the Goddess start to really pick up steam. Avoid.

Things That Fail
: Bottom line: Heal sucks. If you use this, you deserve all the **** your team is about to be giving you for feeding. Chances are, the minor amount of healing you get from this will not be enough to save you, you would be better off with Ghost or Flash
: Just...****ing no. If you get this, you are an idiot and this entire guide has probably pissed you off.
: This is something that supports or tanks can get sometimes...but its definitely not for you.
: You an AD champ or support? No? Move on then.

: This isn't a terrible passive, and in some situations it lets you keep casting long after you would have been 'oom'

****. Yes. This is one of Cass's most important abilities, and you will be using it more than any other for 90% of games. The range is ridiculous, and with a low cost and 3 second cooldown (not to mention that 90% AP ratio), you can spam this like Karthus to push their mid around. This is especially effective against Ashe, since she has to get in range of it to auto-attack you. Noxious Blast+ Ignite+ a couple auto attacks can be an easy first level first blood (Using Twin Fang after level 1), especially if you can tag them with Noxious Blast a couple times while they run back to the turret.
The speed boost can be used to get away, to chase, and to scout bushes (since you only get it if you hit a champion).

: Cass's w is pretty good...its main purpose is to keep people poisoned while you rain **** on them with Twin Fang, and to farm minions with a combo that looks like Miasma and then Noxious Blast. The slow can be used to escape from a losing teamfight, and you if you can place it right, you can sometimes save a fleeing teammate with it.

: This is it. This is the reason the other team hates you. The 1st time you encounter this ******edly strong attack you say "what the **** just happened to my anus?" To properly use Twin Fang, you have to have it on smartcast. (options, key bindings, smartcast. has to be done in game) If you don't use smartcast, you lose about .2 seconds per use of twin fang while you're clicking. This means that you lose every third (potential) attack. Don't believe me? Here's some math: .2*3=.6 The cooldown on Twin Fang is .5 .6>.5, so you are losing one out of every 3 attacks, or 33% of potential damage. Use smartcast, or don't play Cassiopeia.

The main trick to using Twin Fang is to make sure they stay poisoned. It will take a bit of practice to figure out when to use Noxious Blast in a string of Twin Fangs, but you'll get it. Manage to hit someone who is stunned or slowed with your combo and you will be rewarded by watching their health melt away.

: This is one nasty ultimate, probably one of the best in the game, after ******** like Undying Rage.A HUGE arc in front of Cass is hit for a ****load of damage (I have gotten kills from using this), and then either stuns or slows them. The stun can be tricky to pull off, especially if they know its coming, but it wrecks if you can get one off on their whole team. You can also use it to punish someone for face-checking some bushes you're in, or to turn a running fight that you're losing into a standing slaughter that you've already won.

A combo involving your ult should look like this: Petrifying Gaze, Noxious Blast, Twin Fang for as long as possible, then use Miasma on their escape route to slow, and use Noxious Blast and Twin Fang to chase.
Something to note: if you use this on Katarina while she is using her ult on you (and only you), then she will be stunned and her ultimate won't affect you.

In The Begininng...

or
and 2 (not recommended)

I go with Doran's Ring because it is incredibly well rounded, giving you survivability and just a bit more of an early game punch, which is always nice.

Early Game

Sorcerer's Shoes are standard boots for most casters, and the 20 Mpen is self explanatory.
Tear of the Goddess fits in with the general theme of this build: it provides both sustainability and provides additional damage (when you build it into Archangel's Staff).

What order you get Tear of the Goddess and Sorcerer's Shoes depends on who you're laning against and how you are doing. If they have a lot of skillshots to dodge Karthus, Ezreal, Anivia then get the boots. If you are getting pushed around, and feel like you need to hit back a bit harder, then get boots. If you are equal/stalemating, or if you are dominating your lane, then get the Tear of the Goddess first. If you ever have enough gold left over, then buy Elixir of Brilliance. You should do this at every opportunity throughout the game, as it will give you a significant advantage (~30 ap and 10% cdr? Hell yes!)
The Hextech Revolver is up next, and I don't know why I don't see this item in every build for Cass. For only 1200 gold it provides decent ap and kickass spellvamp, mixing survivability with damage output (like I said, a theme in this build). Why is spell vamp so good, you may ask? Well, when you consider that Cass has 2 DoTs with an area of effect, including one that lasts 7 seconds, you realize that she can heal off of minions while she's not even there! This items helps a LOT, and is probably one of the most important aspects of this build ( Tear of the Goddess notwithstanding).

Mid Game

Rod of Ages provides bulk ap, bulk health that is very nice for the squishy little snake girl, and the mana synergizes with your next item:[Archangel's Staff]]
When you finish it, you should see your AP more or less double, and it will keep going up, since the passive on Archangel's Staff stacks with the mana gain from Tear of the Goddess.

Late Game

, or or or or ,

You're next item is the most badass caster item ever created (Zhonya's Ring notwithstanding). Rabadon's Deathcap is nasty, and requires no explanation. Fear the snake with the little hat! (On a side note, if someone photoshops an image of Cass wearing a hat, I will put it in this guide)

The situational/survival item:
Here we have several choices, depending on the composition of both teams and how well you have been doing this game.
Rylai's Crystal Scepter is a good item for chasing, lets you land more Twin Fangs, and provides good health and AP. This is a good item for Cass, and I used to get it every game. I personally feel that there are better things for her to get to increase her survivability and damage, but this is still a great choice.

Banshee's Veil is what you should get against...well, a lot of teams. It is (imho) the best resist item, it's nice for stopping that [Amumu]] or Blitzcrank from initiating a teamfight on your corpse, and it can save you from stuns from *******s like Sion.

Thornmail is to physical dps what your mom is to erections everywhere...death. That Master Yi or Tryndamere giving you a hard time? **** them up with this!

Void Staff kicks a lot of ***, punishing those who dare to stack MR against you. That 80 AP is nothing to shake a snake at either, and this is definitely good...in some situations. You have to use your discretion when deciding whether to get this, since it will be wasted if the only one on their team stacking MR is Shen or something.

Lich Bane. Is. Pwnage. Why is Lich Bane so good for Cass, you may ask? Well, your combo actually goes Noxious Blast+ Twin Fang+Auto Attack+ Twin Fang. In that .5 second delay between Twin Fang, you hit them with an auto attack. This means that Twin Fang procs the Lich Bane's passive every time, making you do around 600 extra magic damage per attack. Sexy good. Also, it gives some magic resistance, which does in fact fit in with the other items on this build. Get this if you think you can get away with it :).

Your last item will be Will of the Ancients. It gives a ****-ton of AP and Spell vamp, rounding out your survivability and damage, and giving your team a nifty aura.If you want to, you can build this sooner, making this 5th.



I see a lot of Cassiopeia builds urging you toward Mejai's Soulstealer. This is...not very desirable. The only time this is a viable item is when you are in elo hell, or if you get VERY lucky. If you use it in a ranked match, or against a team that isn't fail, you will be focused so much that you can't keep enough stacks and will be forced to sell it. My build gets you between 600 and 800 AP end game, without that inherent risk. If you do insist on building a Mejai's, then get it later in the game, when you will get stacks rapidly from kills/assists in teamfights. This is the only time it's viable 90% of the time.

Cass can be in a side lane with anyone with a stun or slow, such as Taric or Alistair. She can also side lane with another poison character, such as Singed and Teemo, as ANY poison can proc Twin Fang. However, mid is where she really shines. The trick to soloing as Cass is to use Noxious Blast like Karthus uses his Q. It has a low mana cost, and with the runes and masteries in this build, you will keep all but the best mids zoned out for a long time.

Just harass with Noxious Blast (and Twin Fang when they get too ballsy) until they overextend or decide that they can kill you. If you harassed well, they will typically be around 75-50% life by the time you hit level 3. Remember to only last hit minions for now, and force them to push out. If they overextend, use Exhaust, Noxious Blast, then Twin Fang that ******* to death. Ignite is also acceptable here.

If you get a kill without taking too much damage, check the position of the other team. If there are no mias, you can push the turret a bit before you b, you can try to gank one of the others, or you can take your blue buff (assuming there's no jungler). If there are mias, stay cautious, keep away from the tall grass (wild pokemon, you know), and keep last hitting minions.

Farm minions, gank side lanes when you can, watch out for ganks, and TALK TO YOUR TEAM. Work out ganks, plan pushes, etc. Call mia for your lane, and call mias for other lanes too, if noone else has.

By midgame you should be ganking, doing dragon with your team (you can solo it around level 10), and participating in teamfights. In those poking engagements before a fight really begins, your job will be to harass as much as possible with your long range, without taking any damage back or getting caught by someone like Amumu, Blitzcrank, Sion, or Rammus.
If you aren't sure you can do that, wait for your team to initiate the fight. Come in after the initial cc goes off, and use your Petrifying Gaze on as many of them as possible. This works best in combination with a taunt, like from Shen, Galio, and Rammus. Next, use Miasma, Noxious Blast, and Twin Fang on their carries, only targeting tanks when there are no other targets available. Your Twin Fang will be the difference between your team winning the fight and losing, so make sure that you don't accidentally hit a target that isn't poisoned, as you will probably get your team killed while its on cooldown.
Teamfights are all the same the whole game, just stay back, don't die, and rape anything that comes near you or your AD carry. Work with your tank/support to stun people in the effect of Miasma, and you will be able to spam Twin Fang at them like no tomorrow.

1st of all, a good rule of thumb about a champion that you are afraid of: play them a few times when they're free, and learn what makes them good and what makes them bad.

These are the ones that I have/have had a hard time with:
Katarina: She is pretty non-threatening before level 6, as you outrange her Bouncing Blades. She is terrifying when she gets her ult, and for a while I couldn't deal with her in mid or side lanes. The trick is to wait until she uses her ult, then to use yours. If you are the only champion around, then she will only be targeting you, and therefore facing you. This allows her to be stunned, then you hit her with Miasma for the slow and Twin Fang her to death.

Tryndamere: His ulti is the most annoying thing on the planet. Again, the trick is to stun him a second or two after he uses it. A good rule of thumb is that if your Petrifying Gaze is off cooldown, then his Undying Rage is too.

Kassadin: One of the few that still terrifies me. His Null Sphere has a range comparable to your Noxious Blast, and it has a silence. He has a built-in flash with Rift Walk, and a good one will make your life hell. I honestly do not know what to do against Kassadin, other than to play super cautiously and to try to set up ganks.

Mordekaiser: Harassing Mord is next to impossible, and unless you can keep him from getting fed early on, chances are his Children of the Grave will kill you. I recommend a Quicksilver Sash or rushing a Banshee's Veil in order to not get pwnd by his ultimate.

Jax: Not many mid, but if you are on a side lane against him, he can be ridiculous. I always underestimate his Leap Strike, and get punished for it. Play cautious, use Exhaust if need be, and just harass with Noxious Blast.

Miss Fortune: Her passive makes her hard to hit with your Noxious Blast, but with practice you should be raping her in no time.

Malzahar: His Call of the Void and Nether Grasp are hard to deal with. The trick is to anticipate the wall, avoid it, and abuse the fact that it has a 9 second cooldown. As for his ulti, I recommend getting a Quicksilver Sash or picking up Cleanse to get out of the suppress (suppress effects aren't mitigated by tenacity effects, either).

Taric: His stun is annoying, but not too terrible to deal with. The only reason he's on here is because he has a heal. This goes for basically all champs with built in heals: only harass if you can get a few hits in from Twin Fang, otherwise you're just wasting your time (usually). Just farm up and wait for the opportunity to burst them down ( Ignite is useful for this, since it gives 50% healing reduction).

Vladimir: Basically all of his skills give him back life, Sanguine Pool is OP as ****, and Hemoplague can kill you if you aren't paying enough attention. Harass is pretty effective against him, and you outrange him. Just stay back, and harass until he overcommits or you out-level him.

More to come later
comments/suggestions/questions welcome :)