Katarina

Strengths

Picking up Daggers will significantly reduce Shunpo's cooldown.
Try waiting until the other team is distracted with fighting your team, and use Shunpo to teleport into the fray and unleash a devastating Death Lotus.
Using Shunpo on an allied Champion, Dagger, or minion can be a great escape tactic.

Passive · Voracity — Whenever an enemy champion dies that Katarina has damaged recently, her remaining ability cooldowns are dramatically reduced. If Katarina picks up a Dagger, she uses it to slash through all nearby enemies, dealing magic damage.
Q · Bouncing Blade — Katarina throws a Dagger at the target that then bounces to nearby enemies before ricocheting onto the ground.
W · Preparation — Katarina gains a burst of Move Speed, tossing a Dagger into the air directly above herself.
E · Shunpo — Katarina blinks to the target, striking it if its an enemy, or striking the nearest enemy otherwise.
Ultimate · Death Lotus — Katarina becomes a flurry of blades, dealing massive magic damage while she channels to the 3 nearest enemy champions.

A suggested 5-lane lineup built around Katarina, based on hero partnerships and role synergy — not win rate.