Assassinate, reset, and repeat.
Burst damage and target access
Hitting a champion with 3 separate attacks or abilities in 2s deals bonus adaptive damage.
Gain a burst of Lethality and Magic Penetration after using a dash, leap, blink, teleport, or on leaving stealth.
Collect eyeballs for champion and ward takedowns. Gain permanent AD or AP, Adaptive for each eyeball plus bonus upon collection completion.
Heal for a percentage of damage dealt with your abilities. Increases with each unique takedown.
9% attack speed, 9 ability power or 5 attack damage
Takedowns restore health and grant bonus gold.
Deal 7% more damage to low health champions. Gain AD/AP after kills or assists.
Electrocute's extra bit of burst damage allows you to finish off a kill to get the resets going.
Katarina can proc Electrocute quite easily with a [Q]->[W]->Auto.
Kat's [E] is a reliable blink that, when paired with Sudden Impact, grants the Magic Penetration needed to assassinate your target.
This loadout is all about kills and snowballing and Eyeball Collection is the rune here that does just that.
Kat naturally likes Spell Vamp as her abilities deal a high amount of base damage and she needs to get up close and personal.
Paired with Gunblade, you'll be healing for insane amounts.
Triumph's extra burst of healing allows you to continue resetting your abilities and killing as many people as possible.
Coup De Grace is the go-to rune when looking to finish off squishy targets quickly. The bonus execution damage synergizes well with Katarina's assassination playstyle.