Maximum damage and execution/assassination potential
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.
Unique champion takedowns grant permanent out of combat MS.
Improved attacks and sustained damage
Takedowns restore health and grant bonus gold.
Deal 7% more damage to low health champions. Gain AD/AP after kills or assists.
Offense
+5 AD or 9 AP
Flex
Defense
+15-90 Health
Electrocute's bonus burst damage is great for early lane poke from [W]->[E]->[Q] as well as all-in damage after 6.
Sudden Impact is easily procced by Zed from [W] or [R] granting the Lethality needed for the kill.
Zed is all about the kills and Eyeball Collection rewards you for doing so by granting you more damage.
If you'd rather keep up constant vision around mid, take either Zombie Ward or Ghost Poro.
Movement Speed is a key stat for hunting down and finding an angle on your prey and Relentless Hunt helps you find those openings.
Kill and cash in, Triumph excels at Zed's natural tendency to want to snowball on kills and get ahead.
Coup De Grace synergizes well with Zed's [R] when looking to execute enemy champions.