First of all; Hello everybody and thanks for reading my guide. This is my first guide but that doesn't mean that it has to be bad. ;)

So, why am I doing this guide?
I have seen so much Cassiopeia guides and nearly every Guide got things like Banshee's Veil in it. Yes, Cassiopeia is squishy but NO you don't have to buy tanky items, because you'll just don't need them. :)
In this guide I want to show you the way of playing Cassiopeia as a beast with much HP, very nice Lifeleech (Spellvamp) and TONS OF DAMAGE.

For runes I choose Magic Penetration Marks, Flat AP Quints, Flat AP Glyphs and Flat Mana-Reg Seals for early game domination. Of course you can use some other runes, but I think these ones are fine. ;)

For masteries I choose a 9-0-21 casterbuild, but again - This is your choice. I just show you how it could look like.

Some of you maybe wonder why I choose this Items and no others.
The answer is clear: When you get focused as Cassiopeia, you are dead. That's a fact. You are a squishy hero and that will not change if you choose one or two tanky items. With this itembuild you will have enough survivability to stay in teamfights long enough. And with the extra spellvamp and that huge amount of HP you can even stay longer in teamfight than with tanky items like Banshee's Veil while doing more damage.
I start with a Sapphire Crystal, one Health Potion and one Mana Potion. If you like starting with Doran's Ring you can also choose it.
Now I try to buy Catalyst the Protector as soon as possible. This will help you alot because it gives you extra HP + MP. By now I'm rushing Rylai's. In my opinion it's the main item for Cassiopeia because the slow + the dots and your W-Spell is just great!

Pros:
- Good harass
- Nice damage
- Ulti can change the teamfight into win
- She's a f**kin' Snake!

Cons:
- Squishy
- Manahungry earlygame
- ...squishy