Deal 7% more damage to low health champions. Gain AD/AP after kills or assists.
Akali loves burst damage and she can quite easily proc Electrocute with a [Q]->Auto->[E].
Akali can make use of both the Magic Penetration and Lethality of Sudden Impact, while nearly always having the proc up with [W] and [R] casts.
Akali loves to kill and snowball. Eyeball Collect is perfect for bloody lanes/games where you're looking to run away with a lead.
Additional spell vamp on top of her passive and Gunblade healing makes Akali incredibly difficult to trade against.
combined with Triumph, she has the potential to easily turn and win a 1v2 if she picks up the first kill.
Triumph on Akali allows you to press you lane damage advantage by potentially snowballing with tower dive kill pressure. the extra burst of healing can be enough to net you the kill without dying and run away with the game.
WhyCoup De Grace
Coup De Grace is an all-around great rune choice the reliable kill damage, especially on an assassin champion like Akali.
If you're playing into a tank top laner and a tank Jungler, Cut Down can be a potentially great alternative choice.