This is my Katarina Build.....first off let me say that im not trying to say this is better then any other build this is just what i use and i prefer it to the AP build and the many spam B.F. sword kat builds. With this build if played right you will be able to move across the map with lightning speed shunpo in death lotus and then use your bouncing blades to finish.
Masteries: I see a lot of Kats building into the defense tree(many 20 in defense) i dont see how this makes sense because you lose the 5% increased magic and physical damage from offensive tree which works double for kat her physical attacks do 5% more and her shunpo/death lotus do 5% more so whether your AP or AD this seems to be a better choice to me.
Runes: I have to test out more rune combos to see what works but personally i like the armor pen and increased attack damage for kat it makes you hit harder and with kat you want to hit harder.
Items: Start off buying 2x hp pots and level 1 boots (thank you HEAT =P), next move onto sword of the occult this will help you a lot because of the increased attack damage per stack and if you can get 20 stacks combined with phantom dancers 15% and boots of swiftness your movement speed will be 507 this may seem excessive but you can nearly outrun an Yi when he ultimates you can definitely stay within range to shunpo and bouncing blades him. Next is rageblade, rageblade is fun because it increases attack speed and ability power so your shunpo hits harder and the 35 attack damage and increased attack speed will make you one tough cookie. After this we go for Madred's Bloodrazer, this is a personal choice you can go for an infinity edge if you would like i personally like the increased damage(im aware infinity does more) increased speed and the 4% magic damage based on their hp if they are heavy with hp tanks go for this but if you want more crit go for infinity, up to you. Next is Phantom Dancer, if you get this far in a game your just having fun running around killing people. Phantom Dancer will give you more crit damage and movement speed plus a bit of dodge for those random matrix dodge kat moments that will piss off the enemy. Finally Black Cleaver this i threw on because the armor pen and increased attack damage will bring you nearly to 400 damage per hit with 20 stacks of Occult.
I tend to take a lane with a partner i like someone who can harass the enemy and keep them back so i can get last hits, Nasus is fun Hiemer is fun anyone u can harass with. As for going mid never tried it i will update it when i do but don't lane against a hiemer his turrets will eat you alive. Start with the boots and pots and pick a lane. Play aggressive with shunpo if you have a good laning partner and farm minions with bouncing blades. Buy occult when you have enough and if you can get some kills and take their tower your having a good game.
Welcome to Mid game home of the gank.
Katarina will be very useful in this stage you can run around to different lanes and gank members of the other teams who have pushed to far or can be easily ganked by the three laners. Get your guinsoo or finish it up if you started it and pick up your madred bloodrazer.
If you have played right your should have nearly 20 stacks of occult if not then maybe the other team is strong it doesnt matter just play ti safe and gank what you can your a ***** in team fights because your bouncing blades can take chunks of life from all 5 enemy champions and then all you need to do is shunpo the lowest hp person closest to you and death lotus watch the enemies scatter and then pick a target and watch your killer instincts/bouncing blades pick off the enemies that are left. With phantom dancer and Black cleaver, if the game lasts this long, you will be deadly and nearly unstoppable in team fights.
Beware of stuns and slows shunpo can be used on ally creeps to get away so dont be afraid to waste it to save your life.
This is my AD Katarina Guide if you don't like it comment why, I'm not afraid of criticism.
I would like to thank HeAt because reading both his AP and AD guides inspired me to test out and make my own Katarina Build. And also for the idea of the boots and 2x hp pots.
Thank you for the feedback and reading my Guide this is my first guide on the site and hopefully not the last.