This is my second build and this time it is featuring

This build is focusing a snowball katarina who will be destroying with her Shunpo

if you enjoy this build Vote it up and leave a comment and if you dont enjoy it/like it then tell me how it could be better

Pros

Amazing damage early-end game
Massive burst AoE Ultimate to set up triples or pentas

Cons

really squishy, Ult can be CC-cancelled
doesnt work too well against high HP champs

i dont know all the best lane buddies but these are some of the ones that worked for me tell me who worked for you and ill add them to the list.

The majority of these are tanky dps because katarina is not tanky at all so having a tanky buddy is nice also someone with CC/Stun is nice too, will add more later

Renekton - is good because he can stun and is tanky
Garen - is good because he is tanky and can dish out some good damage
Rammus - taunt + powerball and he is tanky

As katarina with this runes/mastery/items at level 1 you will be hitting crazy damage on people with shunpo so at level 1 you wanna kinda hang back get your lane buddy to harass a bit then you run in shunpo and eat them. as EARLY as you can, get Mejai's Soulstealer carry on killing people like that until you are considered fed and then just follow the build.

Core Items

Now as you have probably guessed this is a VERY expensive build and it requires either a fairly long game or a hefty feed, usually i get the feed and often my games are long and i still dont manage to completely finish this build, but aslong as you complete Mejai's you will be OP
Sometimes i go for double deathcaps

I focus Mpen for katarina and if you actually have all these runes you can probably skip out on the void staff and get a different item (zhonya's hourglass maybe?) so

Marks
Greater Mark of Magic Penetration x 9
Seals
Greater Seal of Ability Power X 9
Glyphs
Greater Glyph of Magic Penetration X 9
Quintessence
Greater Quintessence of Magic Penetration X 3

I go 9/21/0 for 9 points in offence for 15% Mpen boost and 21 points in defence because katarina is AWFULLY squishy

Offence Tree

Cripple - Buffs up your exhaust even more

Archmage's Savvy - Extra AP is always good

Sorcery - CDR, always good on katarina for shunpo spam

Archaic Knowledge - 15% Mpen stacks with runes to deal 100% true damage with your abilities

Defence

Resistance - Magic resistance, casters deal less damage

Hardiness - Armor, Melee deal less damage

Evasion - 2% chance to block 1 whole attack, could save your life

Nimbleness - after you dodge you get a 10% movement speed boost

Harden Skin - 1.5 less damage taken (100 attacks deal 150 less damage!!!)

Veteran's Scars - 50 more hp

Ardor - 4% AS and AP

Tenacity - 4% less damage taken

Recommended

Flash - katarina being squishy might need an escape and if she cant shunpo to a friendly this is her only chance

Exhaust helps save teammates or guarentee kills

Optional

Ignite getting early kills easy

I learn Shunpo First because as the guides title says we will be focusing shunpo as a nuke
Preparation and Shunpo you should rotate leveling those and obviously level your ult at 6,11,16