Hey Everyone and welcome to my new Hybrid Katarina build, manipulating the new MOBA interface for builds. I thought it was about time I kicked out another build and there is a strong demand for a hybrid katarina. A little note though, elementz is not correct, the best way to play katarina is STILL pure AP, because you are able to get a Hat (which will amplify your AP by 30%) and add 155. This 30% bonus will amplify AP far further than both AD and hybrid. For those who want a hybrid, read further :).
On another note

Stacking on katarina in ranked is NOT recommended, which is why i dont stack my mejais. Stacking is very risky in ranked games, and i might call you crazy if you do, for ranked games on pure ap, you could even follow this build :) I mean the only hybrid item is the hexxtech, (build 1 anyway)

For Runes You Want To Run:

Magic Penetration Marks: Running magic penetration runes gives you an early boost in damage, and shaves off over a third of most character's armor. Also, since all of your skills are armor, I think this is an extremely straight forward choice

HP Seals: Running HP seals gives you that slight edge and ability to survive a bit longer in lane. Seals combined with the defensive mastery starts you with approx 105 bonus HP early game, which is crucial and takes you from a squishy carry to a decently beefed nuker early (having more health than the average nuker).

Ap/level Glyphs and Flat AP Quintessences: Flat and AP per level runes will give you an AP boost not only at the start but noticeably throughout the game. This AP bonus when applied to the Hat will also give a 30% bonus, which will add up to a total of about 55 AP after calculation. This plus the 16 AP due to offensive mastery (at level 18) is about 73.4 AP you would not have had before. I find that to be a pretty big deal

For Masteries i run a 9-21-0 Pattern, getting a full defensive tree for the health, ap % and damage reduction. That AP% stacks on top of your Hat, giving you 34% bonus ap at level 18. In the offensive i get the exhaust buff, the ap/level spec, CDR and the magic penetration spec (percentile penetration is always very good to have)

: Mercury Treads are a great item for someone who's whole game depends on not being CC'd. Kat can't get CC'd or she is basically toast, Mercury Treads Help reduce the time she is CC'd for.
: The Hexxtech gunblade is a great item now that katarina is a hybrid, and is almost a must get. It provides attack, ability power, and spell vamp (which is more important than the health steal even though the health is a bonus). When the gunblade is stacked with the will, you end up with 30%+ spell vamp, which is a huge amount. The active is also great, providing you with a slow and another 300+ damage bonus.
: The Rylai's Scepter, yet another must get on katarina. Rylais makes you 500 health tankier, 80 AP stronger, AND gives you a slow on ANY spell you use. When using your ultimate, that extra dagger on the enemy due to the slow could be the difference between bare survival and death.
: Rabadon's deathcap is the LARGEST must get for ANY AP nuker, katarina is no exception. Sure i will miss the invulnerablility passive but i will enjoy the extra AP, and the extra AP % scaling!. Such a great item and makes your nuke that much harder. Once you get this and have yourself at 500 AP, you are a force to be reckoned with.
: The will of the ancients is a great AP item to get on katarina, it gives you AP and spell vamp, which is everything you could possibly need. If you prefer the CDR route with some bonus damage, grab a Deathfire's Grasp. It gives you a strong initiating nuke and CDR with a good amount of AP. IMO it is just another active i have to worry about :P
: The void staff is your last item because endgame, people will have built up their magic resist, and this will have alot more potency. You want the void staff late game to get the biggest punch out of all your damage. Also, 70 AP is not a small amount to have on an item so i think it is the perfect finish. You can pick up a nashor's tooth along with a deathfire's grasp if you prefer the CDR.

Exhaust: Exhaust is my favorite spell on Kat. It gives you the ability to slow someone in your ultimate, keeping them in place, and the ability to strongly reduce their damage and possibly out DPS them. It also reduces their resistance, giving me the ability to do closer to true damage.

Ignite: Ignite is a great summoner spell because it lets you have more damage tic on someone as you damage them. I usually use it in coordination with my exhaust so that it is going while my ult does, and if my ult doesn't finish them, my ult + ignite does

In teamfights you should never be the one initiating. On the contrary you should be one of the LAST people in, so that all of the enemies have already selected targets. When you go in last, try to shunpo to the back and catch the carries in your ult. Each team will usually have 2 carries, 1 ap and 1 DPS, which will hide behind the tanks. If you take them out, the fight got alot easier because their team no longer has a damage output.