This is my first guide and I wanted to create this unique Katarina build that guarantees game wins and multi-kills. I have more experience than any of the players as Katarina and I have studied every matchup and situation.
Unfortunately not many Katarinas build those temporary items but those items are gamechangers and crucial for all the game situations. Hope you enjoy it!

Typical Runes and Masteries, Armor over any other to provide enough defenses till you reach level 6 - which is what you have to do safely. If you know your matchup beforehand and feel like you won't get bullied in lane I would suggest getting extra AP intead of MR as you might be able to get earlygame kills.

Those are basic masteries which work perfectly as Katarina with any kinds of opponents.
Changing them would be at the cost of other factors which will make it extremely harder for Katarina, not worth it.

Hextech Revolver

The Hextech Revolver is the most crucial item for me as a very experienced Katarina, it is the first item I get with the Sorcerer's boots. With those two items the laning phase will be a million times easier than if you decide to rush other items.

Katarina is all about lane sustain and ganks, you will bully your opponents and get the resets early ;)

You may say those small heals can be replaced by potions, but it's not true as in a fight it provides additional damage and instant heals as long as you keep getting resets you keep healing and survive in the end.

Haunting Guise

The Haunting guise is situational if you need some more health vs opponents that are pretty strong 1v1 like a Gragas, Mordekaiser, Fizz, etc.
NEVER UPGRADE TO LIANDRY'S

Always max W, that is a must. It provides kiting, sustained damage, easier farming, more 1v1 outrade potential, and you get the reset! What else could you wish for?

In this meta you get bot lane combos that have good cc or movement, the teleport is situational: When you have an enemy Miss Fortune with a squishy support I abolutely recommend the teleport. But a lvl 6 teleport on a Leona/Jinx for example will only get you killed, assuming they know what they're doing. As I said it always depends.

Another important case is that if you feel you team wouldn't be able to finish off the first kill in Mid-Late teamfights you should take ignite.
PS: shouldn't have 2 teleports in 1 team and should have 1 ignite at least.

Katarina is a hard champion to master, as many may say she is not, those do not know how much she requires skill to be played. If as they say she is the easiest champion and can just go in a teamfight Pentakill, they are obviously inexperienced.

As Katarina your main goal is to assassinate a squishy target as fast as possible, or getting him low for your team to get you the reset, I will talk about the team role later.
All in all, Get the Reset.. And dont get caught while doing so and die instanly so that your team doesn't insult my favorite champion !

BRONZE/SILVER:

Go for ignite, outplay your enemy, roam bot get kills everywhere.

GOLD:

Go for ignite, have map awareness, buy tons of wards, if you see any opportunity to roam go for it.

Platinum/Diamond

As I said teleport is situational. You have to consider the consequences while roaming, either execute it fast or keep farming till you outpush your opponent or kill or get a gank. Go for the squishiest target in big teamfights but if its a nami support for example dont waste your ult on her, you can just go for a fast unexpected q e w combo and run back. Try getting them low first and flash E to initiate if your team is made of scared players (lol). Never forget Zhonya's, when you go in and dont get a reset it will be very hard for you to work your way out of there as the enemy team will cc chain you.

Pros:

• Second highest damage Ultimate in game
• Great Mobility
• The resets!
• Easy to use multi-target skills

Cons:

• No CC (just the slow from scepter eventually)
• Needs a tank in team to keep enemy team busy and maybe eat some of the stuns while you are sneaking from behind or flashing for the ADC.
• Timing is key
• Requires great skill to be useful

Low Elo

As you may not find any sort of teamwork in low-moderate elo dont whine about it, just find the perfect opportunities to kill that fed adc and tell your team that you need some help to finsih him off. You still need a tank.

High Elo

In high elo consider that your team knows all the champions skills and all you need is wait for the bruiser to go in or wait for the enemies to engage, stay back or on the sides (only if you know it's not warded).
That fight preparation part is crucial as if you get stunned once you may be bursted down and useless, which you don't want to be as AP carry and main damage source.
After the engage pops don't wait too long and go in, get a kill or not, then jump to a ward/zhonyas then jump to a ward ; if you are winning the fight just jump on the next squishy target and the more important one.

Always think about your enemy's skills and the out-trade potential. If it is a ranged LeBlanc that has missed her e and/or w on you don't be scared to just jump in Q E W and you will outrade her. It may seem obvious but keep poking and know that every champion has cooldowns..

A tip for Katarina players: you can juke around by using your Q E W combo and running the other side with that W speed boost, jumping behind a J4 while he combos for a gank for example. That is when your trinket is down or you just wanna troll em'.
[E Range > Q Range by a sliver]

***IMPORTANT*** NEVER make use of your E ability except if it is VERY importan to do so. Always remember, a jungler may be near waiting for you to use your E on your opponent to gank. Getting too close to a ranged opponent with E aswell may waste you a flash or cost you a death.

Flash is more than extremely important for Katarina as she has to use it to position herself and get in range to assasinate the targets.

You do not do that much damage early on, so try hitting the Q first to proc its mark with W and always try to last hit with you autoattacks if you will not get harrassed, otherwise last hit with W and in worst cases E.

Yup, Katarina is not as easy as you thought she would be. This may be my first guide but my experience with her is extremely high. Trust the experts and good luck with your next games!
Happy Pentas!

Quoted:

Is that fear I smell ?

I am thinking of making more champion guides.
Here are the possibilities:

• Jungle Elise
• LeBlanc (featuring jukes)
• Sona
• Lissandra
• Lucian
• Syndra
  
  Those are just some examples for each lane but I master many more and hopefully I can share them with you soon!