Hey everyone,
Thanks for reading my build. This is the first build I've made, so please leave me some feedback.

So Lets take a look at Katarina, shall we? In all fairness, she does quite well soloing against several enemies at once, that is after she gets her ult. I don't know if many of you have noticed, but her CD is reduced on her ultimate if she has managed to use it on someone AND kill them.

My build/guide is used to pwn and gank earlier in the game, this guide is impossible to lose with. How do I know? I've been playing her for ONLY 12 hours and this is by far the BEST build mathematically and experimentally I can come up with. So please, feel free to give it a go in a 5v5 or AI, I would NOT recommend this build for a 3v3, I will be posting an update later for a 3v3.

I feel that it is quite necessary to understand the character you're using in order to use them well.

As a militaristic state, it would perhaps come as no surprise that the primary responsibilities of Noxian women are raising strong children and providing succor for husbands who walk the path of soldiery. There are some, however, for whom nurture is not nature, and Katarina is just such a creature. Born the daughter of the feared Noxian General Du Couteau, the girl was always more interested in her father's knives than in the dresses, jewelry, and other trifles that her sisters spent so much time fussing over. A childhood dispute soon unveiled her uncanny knack for bloodshed, and her father, ever the opportunist, happily fostered her killer instincts. After training under the tutelage of the finest assassins the mighty city-state had to offer, Katarina first cut her teeth performing assassinations in the Ionian War. There, her ruthless mastery of the knife and dagger combined with her sadistic temperament to earn her the title Sinister Blade, a moniker that would follow her for the remainder of her career. She is most famous, however, for her exploits in the campaigns against Demacia, especially those surrounding her engagements with the nation's champion, Garen; a rivalry that began when she recovered the remains of Sion from a vanguard under his protection.

With the demand for warfare somewhat arrested by the tenuous peace settling over Valoran, Katarina sought the allure of violence in its last remaining haven: The League of Legends. Some might say it was an inevitability that Katarina's chosen path would draw her to become a champion of the League, continuing to enforce the will of Noxus and bring prestige of war to her noble family. There, she continues to perform her bloody work - esteemed and reviled, feared and adored.

''The Sinister Blade of Noxus is like a black widow - beautiful, but deadly.'' - Garen, the Might of Demacia, following a skirmish in the field

I'm not going to go into great detail about these because there are many of you using these builds who don't quite have the Greater's yet. So you will want anything and everything that increases your attack damage (AD), attack speed (AS), ability power (AP), and health (HP). You might also want to increase your armor or magic resist if you're worried about ganking. I find that Magic Penetration works wonders late game, but I'll leave that up to you.

I've listed my masteries up at the top. They are only a suggestion, but as I said, many of you aren't to that level yet.

Ok, so I'm going to give you a brief overview of why I chose the items I've listed.

Doran's Blade should come first because it gives you +100 Health +10 Damage +3% Lifesteal

Next you will want boots of some sort, and if you don't have the gold to buy Beserker's outright, I'd start off with Boots of Speed. And the Dagger if you have enough. Eventually come back for Beserker's Greaves

By now you should have enough of a kill strike going that you have enough to go back to base and buy your Bilgewater Cutlass and maybe even your Hextech Revolver.

After you've gotten those Items, purchase your first Hextech Gunblade, and push your second.

As I mentioned earlier, you will want more health and AP, so I'd aim for a Rylai's Crystal Scepter, it gives you +500 Health +80 Ability Power UNIQUE Passive: Dealing spell damage slows the target's Movement Speed by 35% for 1.5 seconds (15% for multi-target and damage-over-time spells).

Finally, for a burst of AD, AP, and AS, get your Trinity Force.

Again, I'm going to stress that this is strictly good for a 5v5 or AI. DO NOT ATTEMPT WITH 3V3!!! You will have your butt handed to you on a silver platter.

This build is helpful for those of you who are good enough with League of Legends to understand the concept of hit and run.

Thanks again,
Rainy