Of the four assassins that received major reworks, Katarina received some of the most notable changes to her kit. The balance team wanted to improve her dynamic laning, as well as offer more opportunities for counterplay for her opponents.
One of the biggest changes: Kat can now Shunpo anywhere around a unit, instead of always behind it. This is controlled by the player's mouse position relative to the target.
Another significant change is her W, which allows her to place a dagger where she is so she can jump to it (yes, she can Shunpo to daggers!).
You can check it all out in action here in her new champion spotlight:
Here’s her full kit, via Surrenderat20:
Bouncing Blade (Q):
11/10/9/8/7 sec Cooldown
Katarina throws a Dagger, dealing 75/105/135/165/195 (+30% AP) magic damage to the target and 2 nearby enemies. The dagger then ricochets onto the ground.
If Katarina picks up a Dagger, she uses it to slash through all nearby enemies, dealing x (+125% bonus AD)(+70% AP) magic damage.
The dagger always lands on the opposite side from where it struck the first target, getting there in the same amount of time regardless of how many times it bounces.
15/14/13/12/11 sec Cooldown
Katarina tosses a Dagger into the air and gains 50/60/70/80/90% decaying movement speed over 1.25 seconds.
If Katarina picks up a Dagger, she uses it to slash through all nearby enemies, dealing 75 (+125% bonus AD)(+70% AP) magic damage.
Shunpo (E) -
10/9.5/9/8.5/8 sec Cooldown
Katarina dashes in the blink of an eye to the target ally, enemy, or Dagger. If it is an enemy, Katarina strikes for 25/40/55/70/85 (+75% total AD)(+25% AP) magic damage - otherwise she strikes the nearest enemy in range.
Picking up a Dagger will reduce Shunpo's cooldown by X%.
Katarina can blink to any location near the target.
Death Lotus (R)
90/60/45 Sec Cooldown
Katarina becomes a flurry of blades, rapidly throwing knives at the three nearest enemy champions, dealing 25/37.5/45 (+22.5% bonus AD)(+25% Ability power) magic damage per knife, up to [15 x dagger damage] damage over 2.5 seconds to each enemy.
Applies Grievous Wounds to all enemies struck, reducing their healing and regeneration by 40%.