One of the reasons Piltover is known as the City of Progress is because it has an extraordinarily low crime rate. This hasn't always been the case; brigands and thieves of all sorts used to find the city-state an ideal mark for plunder, primarily due to the valuable resources it imports to fuel its techmaturgical research. Some even theorize that it would have fallen long ago to the chaos of organized crime if not for Caitlyn, the Sheriff of Piltover. Born the daughter of a wealthy statesman and a pioneering hextech researcher, Caitlyn discovered her natural gift for investigation when, at age 14, her father was assaulted and robbed on his way home. She snuck out of her house that night with her father's rifle and tracked down the muggers from the crime scene. At first, her parents did their best to discourage her from such risky hobbies, but she was incorrigible. Wishing to protect her daughter in the only way she knew how, Caitlyn's mother began outfitting her with techmaturgical devices tailored to her sleuthing needs.

Caitlyn quickly gained notoriety, both because she was single handedly defeating crime in Piltover and also because she soon developed into a ravishing beauty. She never backed down from a case or a challenge, and she was one of the sharpest shots in the city-state. Her services were soon requested by Demacia to help track down a mysterious outlaw who had begun committing high-profile heists. The bandit, who always left a card with an ornate 'C' at the scene of the crime, became Caitlyn's arch-nemesis. To this day, Caitlyn still searches for this cat burglar, and the chase has led her all across Valoran. She has joined the League to hone her skills and gain the influence necessary to track down the only quarry that has managed to evade her.

''Go ahead, run. I'll give you a five minute head start.''
- Caitlyn, from her book 'Willing Apprehension'.

PROS

Heavy early damage
Lane control (traps for evade ganks)
Sniper
Easy farm
Nice passive
Free kill with lizard buff

CONS

Squishy
Focused by enemies
Must be feed to win mid-late
Enemies can protect her ulti
Needs mana regen

We need a lots of armor penetration, because we deal attack damage and our most dangerous skills deal physical damage too

We need mana regen

Caitlyn is a ranged carry AD so we build 21/0/9

Important masteries:

Armor penetration
Damage
Havoc
Ghost
Experience

First skill must be your trap, to prepare and help on lane
Second and most important skill, your peacemaker
Three skill must be your net, could help you on early jungle ganks.

level 1-W
level 2-Q
level 3-E

You need to max your Q after level 3

R > Q > W > E

Flash + Ghost makes you difficult to kill.

Flash + your net save you so many times
Ghost + lizard buff let you chase enemies and kill them
Ghost helps you dealing some damage before using your ultimate

Your goal on early game is hard farming:

You must prepare your lane with traps, one trap on river bush, one trap on each lane bush.
You must take all last hits and try to harrass the enemy.
Your Q and your range help you to take first blood or a couple of kills, if your trap catch someone, Q + autoattack and you have a free kill.


CORE EARLY BUILD:
Doran's blade
Boots
Doran's blade
BF Sword

Caitlyn really needs a good farm, some tips:

You can hide on bushes to recharge your headshot (passive) and dealing extra damage to kill the creep.
You can use your "Q" to kill far low hp creeps

Now is the moment to carry your team.
Your traps stun enemies
Your Q destroy them
Your ultimate made +1k damage
Your net and summoner spells evade all focus

Caitlyn is a damage dealer, Peacemaker and Ace in the hole (Q and R) scales so much damage so you must buy lots of damage, the best item for Caitlyn is the bloodthrister mixed with last whisper and black cleaver, you destroy enemie's armor and deals tons of damage.

I love banshee's veil, protect you from engage skills like ashe's arrow, amumu's stun or morgana's prison for example, and give you magic resist, hp and mana. Epic item.

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