"While her sister Katarina has always been the most celebrated member of the household, the
Du Couteau family has a long history of service to Noxus. It is often been said that no
soldier has ever been as fortunate as General Du Couteau to have been graced with
daughters. His youngest, Casiopeia - despite lacking her sister's killer instincts - was
equally renowned in court for her stately character and elegance. Cunning as she was
beautiful, the temptress could never be found far from the arm of any foreign dignitary,
her wiles prying secrets from the lips of even the most wary attache. With the Noxian
barbarian pacification campaign having ground to a standstill, Cassiopeia had set
her sights on a diplomat from a tribe of the Freljord region. Thinking him an
easy mark, the scheming seductress set about beguiling him. He refused to confide in
her, however, until she swore an oath of secrecy upon his sword - a strange weapon
with a serpentine curve to the blade.

Once her tryst was over, Cassiopeia provisioned her father with information regarding the
barbarian resistance. As she divulged this intelligence, a wave of revulsion washed
over her. She screamed in agony as her silky skin hardened to scales, her lustrous
hair thickened to leather, and her manicured fingernails sharpened to claws.
Dazed, she fell upon a group of horrified servants, rending them limb from
limb in a heartbeat. When it was over the blood-soaked figure was no
longer the ravishing jewel of the Noxian court, but a horror trapped
somewhere between woman and serpent. Unable to serve in her
traditional capacity, Cassiopeia departed for the League,
continuing her service to the Noxus on the Fields of Justice."

Cassiopeia was introduced to the League of Legends on December 14, 2010

ProsCons
+ Has an amazing poke
+ Does a lot of poison damage
+ Has very fast casting
+ Can both slow and stun
+ Has very high damage
- Squishy
- Hard to master
- Depends highly on mana
- Huge target
- Skill shots

Deadly Cadence

Deadly cadence is a perfect spell for Cassiopeia since she relies so heavily on mana. It gives you the ability to cast multiple spells or abilities in a row for less mana than it would normally cost.----
Noxious Blast

Noxious Blast is your poke move. You can use it on enemies in order to poison them and do damage. The reason why yo want to maz out this move first is because you can pair it with Rylai's Crystal Scepter so that it also slows enemies. In addition to that, you need to make sure that you practice using it before jumping right into a PvP. This move is a skill shot move, because as soon as you click your "q" it goes into effect, unlike other abilities where a target will show up first. It can be hard to land, but is super effective when it is mastered.----
Miasma

This is supposed to be your last move maxed out. It does slow, but it only poisons, and does not do any further damage besides the damage from that poison. It can be seen by enemies, but can still be effective if done correctly. It does aid before you build up Rylai's Crystal Scepter because of its slow, but is also better to be mastered before you go into a PvP.----
Twin Fang

The reason why twin fang is one of my favorite moves is because if it hits a poisoned target, it has literally no cooldown. It does massive damage, but also requires a lot of mana. However, if you time it right and cast it correctly with Deadly Cadence then you can find yourself killing your opponent in a matter of seconds.----
Petrifying Gaze

This move can either stun or slow your enemy, which is why you want to make sure that you master it also before you enter a PvP. It can be used offensively in order to stun an opponent, do damage to them, then follow up with other abilities, or it can be your lifesaver, and stun them as you make you escape with 10 health. However, even if you miss your target and they are turning the other way, it is nice that it will also slow your enemies.----
Combinations

Throughout a series of tests and games, I found that there are 3 different combinations that I have found for Cassiopeia. These consist of early game, mid game, and late game combinations. Each combination is similar but unique from each other at the same time because of its end effects.

Early Game Combination - By this point, I would hope that you have a strongish Noxious Blast. Your other abilities are all lower level, and will act as support for after you attack your enemy with your "q". It can also be paired with Ignite so that you can guarantee the kill.

Mid Game Combination - By this point, you will have a strong Twin Fang as well as Noxious Blast. You still do not have your ultimate ability, but you can still do major damage by first slowing your enemy with Miasma.

Late Game Combination - Finally by this point, you should have all of your abilities, and can use the final combination that follows. You want to use your Miasma first to slow, but put it behind your enemy, then quicky use your ultimate to stun them or slow them. This way, even if your stun misses, they will be slowed massively by both Miasma and Petrifying Gaze. Then, work your magic with the rest of your abilities.