Hello :3 MaliciousBunface here, I guess I decided to write a guide/build for Cassiopeia, as she is a unique caster that can be very deadly when played effectively.

This guide will contain helpful sections such as:

~Runes
~Masteries
~Items
~Play style
~Strategy
~Miscellaneous

P.S I use a touchpad, so if I can aim then so can you :3
<-- I don't know how to fix it, but right click it and open it in a new tab to view it :3

Pros
Strong character in general
Unique abilities
Never been nerfed
Snake :3
A very powerful kiter and chaser

Cons
Can burn mana with Twin Fang (Very quickly)
Squishy
Fails hard if you can't aim your Q, W or your ult.
6300 IP
First champ with 100 difficulty

For my rune page, I use Flat AP quints, Flat AP seals, AP per level glyphs and Magic pen. marks.

~ Random thing that you may want to consider is that if you use 8 flat AP seals and 1 AP per level seal, you will still have 20 AP at level 1 and 30 at level 18 instead of 28. Not much of a difference, but whatever :3

Personally, all you need from the Utility tree is movement speed and buff duration which is why I use 21/0/9

If you want to use 9/0/21 then that is fine, more exp so you will most probably get to level 6 first.

Well, I start with a Doran's ring for the AP, health and mana regen. This puts me onto 43 AP at level 1. I stack 3 rings, for a strong early game. With boots, it will be hard for enemies to get away, and boots of swiftness increase your ability to chase and kite.

After this, I go for hextech revolver for the useful heal, which will benefit you the second you buy it. After this, I go for Rabadon's Deathcap which will normally put me on around 350 AP. After buying Deathcap, everything is situational. If you need the slows, get Rylais. If you need more damage, get Abyssal Scepter. If you need more spell vamp or want to give allies the aura, get Will of the Ancients. If you burn too much mana and can't get blue buff, get Archangels. There are other choices, like Rod of Ages or Zhonyas, but the items I recommend you don't get are Deathfire Grasp and Lich Bane.

DFG: Most players normally forget to use it, and you have enough burst damage without it.
Lich Bane: You don't have time to AA in between Noxious Blasts and Twin Fangs, plus it is really expensive considering you don't benefit from a large part of the item. The MS is nice though, but I don't recommend it.

I take Flash and Ignite, Flash can help close the gap (as well as escape) and Ignite is good for pesky champs like Xin, Sion etc. (Anyone with heals or escapes)

I have been taking Teleport recently, it gives you the ability to recall and go back mid quickly, and strong pushing power late game.

Exhaust isn't too bad, I used it when I first played Cassiopeia, good slow to get more poison on them, or strong 1v1 abilities.

I don't recommend the following Summoner Spells:

~Clarity - You should already have MP/5 with Doran's, and you should learn mana management. Leave it to a support, but you shouldn't be in a side lane anyways.
~Heal - You really shouldn't need it, but you can bait people with this and your ult I guess.
~Promote - Well, it's not really a spell for an AP carry to have.
~Clairvoyance - It is useful, especially if you gank a lot, but you shouldn't be the one to bring the spell.

The skill sequence I have is the one that I find the best. With Noxious Blast at level 1 and Twin Fang at level 2, you can start to heavily harass enemies and possibly kill. This is pertaining to the fact that you can aim with your Q.

Miasma is gotten at level 4 in case you have enemies that move a lot and need to zone them out, or if you need a slow.

Twin Fang is maxed out first (2/3/5/7/9)
Miasma second (4/8/10/12/13)
Noxious Blast last (1/14/15/17/18)
Petrifying Gaze whenever you can (6/11/16)

Some players max Noxious Blast first, which can work depending on the situation. But if you do skill like this, your 1v1 damage potential is reduced severely as Twin Fang won't be doing the damage.

Passive. Is. Very. Useful.

Deadly Cadence is possibly one of the best passive abilities in the game. A useful tip; The reason I don't max NB until late game is that at level 1, you can constantly use it to keep your passive at 5 stacks, and not lose mana because of your three rings.

Growing. Poison. Is. Growing.

An expensive, but useful spell, a slow that grows and possibly has one of the largest damage outputs a normal spell can have. Use it wisely, in terms of zoning out opponents or just hitting them with it so they are slowed for 2 seconds. Always try to catch people in this, and make sure you use it before you ultimate them.

Although it is a blast using your Q, it is quite boring if you can't hit them with it. Bunface tips for Noxious Blasting are here to help :3 0.9 AP ratio is fun AP Ratio :3

Always check the range of it, and try learning it. Normally, if you are attacking melee minions, you will be able to hit anywhere up to just past the ranged minions.

You may have heard this before. Try predicting where the enemy will move. If you want to try and force them to move in certain ways, move forward a bit and wait til the start moving back. Then cast Noxious Blast a bit ahead of them, and proceed to face roll them with your combos.

Don't face check. Face check = Face roll. Use your Noxious Blast to check brush. If an enemy Champion is in the brush, you will get a movement speed boost. And it doesn't hurt your mana pool as much as a miasma would.

You can cast your Miasma on the enemy caster minions to force the champion to stay away, or come closer to you. Either one of these are okay, as you can harass them in terms of damage or experience. Be wary of your mana though, as it is not cheap.

Blue buff will make the CD as long as the duration. Random fact.

Don't use it to farm minions unless you have blue or need to push fast. Be smart, and try not wasting it.

Please. Make. Sure. They. Are. Poisoned.

Even I make this mistake, and 4 second CD is not fun CD. It can completely waste your ultimate as well, as 2 second stun = ~3 Twin Fangs. You screw up and you have to wait another 2 seconds after the stun ends to hit the, with Twin Fang.

Your ultimate is a very strong damage spell, as well as a vexing CC if you are hit. The stun and the slow are both bad, so you should try and use this spell to hit a lot of enemies. But, try to stun their deadly carries and what not, as that is what you should be trying to do anyways.

Fail. Bait. Is. Very. Fail.

Don't fall into your own trap. Pretty simple, I do it rarely. You run back, baiting them. Then when you go to ult, they have already started running back and dodge your ult. It's sad, and embarrassing. Plus there is a long CD too.

Your ultimate is also your main escape/initiate spell, so be wary when using it.

This shouldn't really happen. Unless it is solo top. But even then, there should be a better candidate for solo top.

If you do happen to be duo top or bot, lane with Soraka, Twitch, Teemo or Singed. They poison so you don't have to, except for Soraka but walking mana and health supply is support :3

Mid is Cassiopeia's home (:

As obvious as it may be, silences and stuns will shut you down. Make sure that you are positioned well enough to make them overextend, if they still want to kill you.

Noxious Blast and Miasma combined are powerful escape tools, as well as chasing.

If you have spell vamp, you can kite people when you are low health, healing with Twin Fang and then turning the chase around to kill them.

Although you are a good kiter, be wary of enemies that my come to help with a silence or a stun. Your death will be guaranteed if you do not play wisely.

When you have your hextech revolver, you will be able to clear caster minions with two Noxious Blasts for a period of time, and you can use miasma to get the melee minions. With your mana regeneration, farming is easy for Cassiopeia mid game.

A unique, high tier AP carry. A good Cassiopeia will be your greatest ally or your worst enemy. I hope you liked my build and tips, please comment if you feel like it, and don't be mean :3